December 2015

Vytor has finished his investigation of halogen bonding. He shows that coupled cluster calculations are essential to correctly describe halogen bonding. He has investigated 120 halogen-bonded complexes and his interesting results will be the basis of several publications.

November 2015

Chengfei finished a plotting program that reliably presents difference densities in form of conturline diagrams and 3-dimensional perspective drawings. The program will be needed for the method development part of CATCO.

November 2015

Bruna summarized her calculations to determine the pKa value of amidines. Her investigation presents the first step to verify the activity of a new anticancer drug Elfi and Dieter designed on the basis of electronic structure theory.

November 2015

Terutaka and Dieter are close in getting second order response properties at the Dirac-exact 2-component NESC level correctly programmed. The coupled perturbed GHF part is running and the first results come in. However, there is the need to make programs more efficient.

November 2015

Thomas attended The 67th Southeastern and 71st Southwest Regional Meeting of the American Chemical Society (November 4-7, 2015) in Memphis and presented in an invited talk the results he and Dieter obtained on Cu-catalyzed 1,3-dipolar cycloadditions. The title of his talk reads: The pivotal role of dicopper catalysis in 1,3-dipolar cycloadditions: A reaction valley study.

October 2015

Elfi presented on October 15 a CATCO-research seminar at the Department of Chemistry, University of Alabama at Birmingham, under the title "URVA Analysis of Catalytic Reactions." She talked with faculty interested in our work on CADD and local vibrational modes.

October 2015

Marek carried out a systematic study of all reactions analyzed with URVA. His investigation gives the basis for systematically improving the analysis of URVA results.

October 2015

Yunwen and Elfi made important progress in setting up the computer program for carrying out URVA with a QM/MM approach, which is needed for the investigation of enzymatic reactions. Yunwen has started to get the vibrational frequencies correctly programmed for the QM part of QM/MM because the frequencies along the reaction path are needed to detect path instabilities and to assess the reliability of an URVA study.

September 2015

Elfi and Dieter attended the BIT’s 6th Annual Congress of Catalysis 2015 in X’ian, China (September 24 – 28), and presented their work on Criteria for an active catalyst (Elfi presenting; co-authors: Marek, Wenli, Thomas, and Dieter) and on Homogeneous Catalysis and the Tolman Electronic Parameter (Dieter presenting; co-authors: Dani, Wenli, Rob, and Elfi). After the congress, they used the chance of visiting Chinese research groups in chemistry and computational chemistry.

September 2015

Wenli and Dieter finished their study on the question whether dicarbon (C2) has a quadruple bond or not. They carried out MR-AQCC(8,8) and MR-CISD+Q(8,8) calculations to demonstrate that the stretching force constant, the energy density, and electron density of the molecule suggest a 2.5 bond order rather than 4. They studied dicarbon in the box and showed how under confinement conditions bonding of the molecule can be studied.

September 2015

Nick who arrived in late August gave a presentation on the trans-effect in transition metal chemistry. He will work on this topic because an understanding of the trans effect is essential for homogeneous catalysis involving transition metal complexes.

September 2015

Wenli, Chengfei, and Dieter made an investigation on how to accelerate the convergence of geometry optimizations based on puckering coordinates. Cycloheptane and cyclooctane are investigated by Wenli and Dieter. They succeeded in deriving for the first time general formulas describing ring pseudorotation in these rings.

August 2015

Olalla started an investigation on the mechanism of Au(I) and Au(III)-catalyzed ß-eliminations. URVA reveals characteristic differences in the mechanism and explains the larger effectiveness of Au(I) in the reactions. The study is supposed to be finished in November.

August 2015

Dani and Dieter have redone the investigation of the Tolman Electronic Parameter (TEP) by increasing the number of compounds investigated from 42 to 176 and also including many sterically congested Ni-complexes. They come to the surprising result that the TEP is highly unreliable and in most of the cases simply wrong. In view of this, they establish a new electronic parameter that directly measures the metal-ligand bond strength via the local ML stretching force constant. The MLEP, as they have dubbed the new parameter, gives quantitatively and correctly the different metal-ligand bond strengths and provides a revealing insight into the electronic structure of transition metal complexes.

August 2015

Carlos, Olalla, Marek, Elfi, and Dieter have summarized their study on pseudopericyclic reactions, which represents according to Carlos a breakthrough in the basic understanding of pericyclic reactions. Definitely, the study is an excellent example of how to successfully carry out URVA investigations.

August 2015

Carlos, Olalla, Elfi, and Dieter carry out an investigation of ketene cycloadditions, which seems to be mechanistically similar to the pseudopericyclic reactions.

August 2015

Terutaka, Wenli, Michael, and Dieter work on an extension of the analytical gradients of the Dirac-exact 2-component NESC method. This requires new integral derivatives and a lot of programming. Targeted are the correct calculation of contact densities, Mossbauer shifts, electric field gradients, and hyperfine structure constants.

August 2015

Wenli left to start his own academic career in China. He was essential for a larger part of the programming work in the CATCO group, especially with regard to Dirac-exact relativistic methods and the new program generation based on local vibrational modes. Wenli was one of the hardest working people in the group as is documented by the many papers he published with Dieter. Apart from this, everybody liked him because he was always prepared to help the younger group members. We all will miss him.

July 2015

Carlos and Dieter have found a way of distinguishing between pericyclic and pseudopericyclic reactions utilizing URVA. Carlos could demonstrate that the transition from a pericyclic to a pseudopericyclic mechanism is continuous contrary to what Dieter and Elfi anticipated. This is essential for a better understanding of the role of charge transfer and charge polarization in chemical reactions.

July 2015

Terutaka arrived on July 6 coming from Tokyo. Bruna arrived on July 20 coming from Brazil. Bruna will work on the calculation of pKa values, which is important for the drug-design work of Elfi, whereas Terutaka will pick up Wenli’s work on Dirac-exact 2-component relativistic methods.

July 2015

Wenli and Dieter are writing up manuals for the CATCO programs. This work was always delayed but became now of utmost importance since the multitude of programs either written in the group or obtained as new working tools has led to the fact that no longer every CATCO member knows what is possible and how a given problem can be solved by what is available.

June 2015

Olalla and Dieter are working on the Rautenstrauch reaction, which is a typical example for an effective gold catalysis. They use URVA results to predict whether substitution can lead to a lowering of the barrier. In this connection, Olalla has made a very detailed curvature analysis of the most important reaction steps.

June 2015

Wenli and Dieter have a first set of curvilinear coordinates to describe transition metal complexes. However, it I will be a long way to apply them in a routine way. A lot more programming has to be done for this purpose.

June 2015

Chengfei has intensified his work on chalcogen bonding where he investigates a series of covalently and non-covalently bonded systems. He will quantify the strength of these interactions with the help of the local vibrational modes.

May 2015

Sally arrived and quickly got all administrational problems solved. She learns now to use the various computers in one-week courses, which are arranged by either CATCO or SMU. She will work on H-bonding and ring pseudorotation in ribofuranose.

May 2015

Thomas and Dieter have started to investigate the Cu-catalyzed 1,3-dipolar reactions. The visit of Adam Viege, University of Florida, of CATCO on April 9 and his seminar on April 10 (New Approaches to Synthesizing Conjugated Materials: Inorganic Click and Cyclic Polyenes) initiated these studies. The number of Cu atoms involved, the Cu-ligand, and the solvent strongly influence the catalytic activity, which can be quantified utilizing URVA as a tool.

May 2015

We congratulate Rob for his new job with SMU, which gives him an excellent opportunity to apply his talents in hardware and software development. He is the first CATCO student at SMU who got his Ph.D. and we are happy to see how his career develops in a very positive way.

May 2015

Alan has started to investigate metal-metal bonding with special focus on quadruple, pentuple, and hextuple bonding. His investigation on MM diatomics indicates that ditungsten and dimolybdenum have surprisingly strong bonds. Alan will have to show whether one really can speak of hextuple bonds.

May 2015

Elfi gave a presentation in Waco on May 20. She was an invited speaker for the Stone Symposium: Main Group Chemistry and presented her, Dani’s, and Dieter’s work on phosphine interactions under the title: Pnicogen Bonds: Fact or Fiction.

May 2015

Wenli has brought a 1-year long work on curvilinear coordinates to a first ending. He and Dieter study the Berry pseudorotation and are able for the first time to describe a 2-dimensional analytical surface on which the rearrangement takes place. Wenli and Dieter can develop now curvilinear coordinates for other rearrangement processes such as the turnstile pseudorotation, the Bailar or Ray-Dutt twist, or the Bartell pseudorotation.

April 2015

Dani studies together with Elfi and Dieter the question whether the shorter bond is always the longer bond. They have identified a number of molecules, for which the Badger rule is violated. Previous work on this topic avoided an analysis of these bond anomalies because this phenomenon seems to avoid common explanations. By establishing a clear concept how different electronic factors can lead to bond anomalies, Dani, Elfi, and Dieter can explain all cases observed so far with the result that the project is rapidly extended to more and more cases with bond anomalies. Several papers are planned.

April 2015

Yunwen studies together with Wenli, Wei, and Dieter water clusters to find out when their properties approach that of liquid water. They have discovered a large number of different H-bonds, which are currently categorized with the help of newly developed criteria.

April 2015

Olalla and Carlos have arrived who will carry out together with Marek, Elfi and Dieter investigations on Au, Pt, Pd catalysis utilizing URVA. Carlos wants to re-investigate the pseudopericyclic reactions to find a better rationale for their low or non-existent barriers.

March 2015

Wenli and Dieter have finalized the curvature component analysis for URVA, which represents a quantum leap forward in analyzing the reaction path curvature in cases where path instabilities lead to imaginary vibrational frequencies. The latter make it impossible to analyze the scalar curvature in terms of local vibrational modes. However, this problem is now solved.

March 2015

Thomas and Dieter made a step forward in identifying bifurcation points in a chemical reaction. Thomas changed the numerical grid and the optimization criteria of the DFT calculations and, in this way, was able to follow a ridge path starting at a valley ridge inflection point to a certain extend. The higher accuracy leads to later and larger curvature peaks because the actual path follows the ridge longer and curves down to one of the flanking reaction valleys more sharply.

March 2015

The special issue of J. Phys. Chem. A appeared, which was printed on the occasion of the 25th Austin Symposium with Dieter and Elfi being the guest editors. The issue contains a total of 40 contributions from the participants of the conference, which took place in honor of Jim Boggs early March 2014.

March 2015

Alan is still sitting on the hexaphenyl ethane investigation, which is essential for his CC bond studies in connection with the question: What is the longest CC bond ever observed in Organic Chemistry?

February 2015

Yunwen has started together with Wenli and Elfi to rewrite the URVA program. This has become necessary as for large molecules the storing of the mass of data generated during an URVA study can no longer be stored during the calculation, especially if enzymatic reactions are studied. Hence, the URVA analysis has to be done on the fly rather than after the calculation, which involves a rewriting of the whole code.

February 2015

Vytor together with Elfi and Dieter started a systematic study of halogen bonding. They are especially looking for covalent halogen bonds and how they differ from non-covalent halogen bonds.

February 2015

Marek, Dieter, and Torsten have substantially improved the reaction library. It is contains now the movies of Thomas and many additional details. However, a lot of work has still to be done until this can be presented to the public.

January 2015

Wenli and Dieter are working on the curvilinear coordinates, and extension of the local mode description, and an extension of the reaction path analysis. They have set up a time schedule for getting several projects related to this topic finished within a year.

January 2015

Wenli and Dieter are sitting on a local mode stand-alone software package. Wenli has made it compatible with about a dozen different programs, however many more problems have to be solved to make the program smoothly applicable for the non-trained user.

January 2015

Zhanyong and Dieter summarized their work on the APSA method to determine structure, similarity and folding of proteins. Their new conformational alphabet works fine in a number of test cases. A new approach to the description of protein folding has been developed. In the future much work has to be done to generalize the APSA approach.

December 2014

Yunwen, Wenli, and Dieter are working on a QM/MM version for the calculation of locl vibrational modes for proteins.

December 2014

Chengfei, Wenli, and Dieter are working on a program to identify and characterize H-bonds in water-clusters and liquid water. The aim of the project is to distinguish different classes of H-bonds.

November 2014

On November 26, Thomas presented to faculty and students his research results on homogeneous catalysis: "Studies in Homogeneous Catalysis Based on the Unified Reaction Valley Approach."

November 2014

On November 21, Paul Schleyer passed away. He was a teacher, mentor, and friend of Dieter who introduced Paul to the CATCO group at several occasions. The chemical community will miss Paul very much.

November 2014

On November 19, Elfi presented at the 70th Southwest Regional Meeting (SWRM) of the American Chemical Society at Fort Worth, TX (November 19 – 22) together with Marek, Wenli, and Dieter the CATCO research on the mechanism of catalyzed chemical reactions. Title: "Criteria for an Active Catalyst."
At the same conference, Dieter together with Alan and Wenli gave a talk on unusual bonds. Title: "What are the longest CC bonds in Chemistry?"

November 2014

On November 12, Dani presented to faculty and students his research results on pnicogen bonding: "Pnicogen Bonding: A new Type of Closed-Shell Interactions Important for Materials Science."

November 2014

On November 5, Alan presented to faculty and students his research results on long CC bonds: "Investigations Into the Longest CC Bonds Observed in Chemistry."

October 2014

Dani determined Coupled Cluster geometries and binding energies for pnicogen-bonded dimers, which significantly correct the previous DFT results. According to these values, the strongest pnicogen bonds are comparable to H-bonds.

October 2014

On October 5-10, the 10th WATOC meeting of the World Association of Theoretical and Computational Chemists took place in Santiago de Chile. CATCO group members delivered two of the invited lectures. Dieter talked about "Novel Tools to Analyze Chemical Bonding and Electronic Structure Based on Vibrational Spectroscopy" (together with Wenli) and Elfi talked about "New Features of The Unified Reaction Valley Approach – From Simple Exchange Reactions to Homogenous Catalysis" (together with Marek and Dieter).

September 2014

In the last two years, Marek has extended the reaction library by 154 catalyzed chemical reactions involving Au, Cu, Ni, Pd, Re, Rh, Ru, Ti containing transition metal complexes. The calculated reactions have been uploaded to the CATCO reaction library (www.reactionlibrary.org), which includes now a total of 358 catalyzed and non-catalyzed reactions. Each chemical reaction investigated is characterized by diagrams being based on results of the URVA analysis, the reaction energetics, coordinates of all stationary points, reaction videos, and snapshots determined at the curvature minima of the reaction path. Marek’s work is complemented by the studies of Thomas on catalyzed Diels-Alder and 1,3-dipolar cycloaddition reactions.

September 2014

Alan and Dieter finalized their work on bridged [10]annulenes focusing especially on the 11,11-dimethyl-1,6-methano[10]annulene, which is the most unusual system in chemistry. It carries out a large amplitude vibration in a slightly asymmetric single-well potential resulting from the fact that the valence-tautomeric bisnorcaradiene form has almost the same enthalpy as the [10]annulene form an can interconvert without activation enthalpy! The correct description of 10 pi-electron delocalization requires high order dynamic electron correlation with infinite order effects. The rapid closing and opening of the 1,6-bond lead to a biradical with strong delocalization including sigma and pi-electrons. The minimum active space for a correct description of these effects is a (14,14) active space. On top of this, the interactions of the methyl groups in the bridge with the pi-perimeter have to be correctly described. Hence, 11,11-dimethyl-1,6-methano[10]annulene is one of the most difficult closed-shell systems ever investigated.

August 2014

Chengfei and Yunwen have arrived from Shanghai. They will make their PhD in the CATCO group. Together with Vytor who started already in January 2014, they will form the CATCO class of 2014. We welcome all three of them and wish them much success in their research.

August 2014

Wenli is working on the stand-alone program for local vibrational modes that will provide additional possibilities for calculating the local modes of van der Waals complexes.

August 2014

Zhanyong and Dieter are working on a user-friendly version of the APSA program for the protein structure description in terms of Frenet coordinates. They plan to make it publically available in 2015, which however requires a better use of the vector presentation of the secondary structural entities.

July 2014

Wenli, and Dieter are working on a new set of curvilinear coordinates for transition metal complexes. The generalization of their approach is at the moment the major problem. However, they have solved the problem of describing the local modes of pi-complexes by using suitable mass- or charge-centered curvilinear coordinates. This helps proceeding with Marek's and Elfi's chirality investigations.

July 2014

Dani, Elfi, and Dieter have discovered a new type of PP bonding directly related to pnicogen bonding. MR calculations have to verify the nature of this new type of PP bond.

June 2014

The reaction library has obtained a new, more professional appearance thanks to the work of Tristan. It can be viewed on cell phone, tablets as well as laptops. For all stationary points, optimized Cartesian coordinates are given. Thomas has included movies for all reactions investigated. A variable table format guarantees that the energetics obtained can be compared with available experimental values or the results of other quantum chemical studies.

June 2014

Dani, Elfi, and Dieter worked on pnicogen bonding investigating a variety of different E,E' through-space interactions (E, E': N, P, As, Sb), which can be covalent or electrostatic in nature. They established a set of 40 pnicogen-bonded dimers, for which they used local vibrational modes, electron and energy density distributions to determine the nature and the strength of the pnicogen bond.

May / June 2014

Elfi and Dieter made a 4-week lecture tour through China. They visited Shanghai (SIOC and Fudan University), Xuzhou, Nanjing, Chengdu, Lhasa, and Changsha giving 13 different lectures together. The meeting with Chinese colleagues both from theory and experiment was a positive experience, which will have long lasting effects. New scientific collaborations were established. Here are some of Dieter’s topics:

  1. Investigation of Protein Structure with Quantum Chemical Methods: Hydrogen-bonding and Protein Similarity, Plenary lecture, 4th International Symposium on Organic Synthesis and Drug Discovery, Xuzhou, China, May 23-25, 2014
  2. Investigation of Protein Structure with Quantum Chemical Methods: Hydrogen-bonding and Protein Similarity
  3. The Use of Vibrational and Nuclear Magnetic Resonance Spectroscopy for the Determination Protein Secondary and Tertiary Structure
  4. The Automated Protein Structure Analysis: Description of Protein Folding
  5. Description of Electron Correlation in Quantum Chemistry
  6. Development and Application of the Dirac-exact Normalized Elimination of the Small Component (NESC) Method for the Calculation of Relativistic Molecular Properties, Plenary talk, 3rd Changsha International Workshop on Theoretical and Computational Chemistry with Materials, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, China, June 8-10, 2014
  7. Dancing Atoms and Molecules without a Structure

May 2014

We congratulate Dieter for being named Ford Research Fellow at SMU’s Board of Trustees meeting on May 8, 2014.
Dieter Cremer 2014 Ford Research Fellow

May 2014

Vytor is working on halogen bonding. He has systematically varied the halogen donor and the acceptor. It is obvious that there are similarities between H-bonding and holgen bonding on the one side and pnicogen-bonding and halogen bonding on the other side. Vytor applies three tools: i) analysis of the local stretching force constants, ii) the topological analysis of the electron density distribution in connection with an analysis of the energy density distribution, iii) an investigation of the electron difference density distribution in connection with the PMO analysis.

April 2014

Dieter presented a plenary lecture at the 14th DeMon Developers Workshop, Los Cabos, Baja California Sur, Mexico April 27, 2014 with the title "Electron Correlation as Described by WFT and DFT Methods." Travelling is sometimes dangerous. The wonderful and very comfortable conference hotel was washed away by a hurricane some weeks after the meeting.

April 2014

Thomas is getting an extremely improved insight into the Diels-Alder reaction. He can identify now the orientation of diene and dienophile, then the step where the gauche form of butadiene is forced to planarize. Similarly, he sees how the boat form of cyclohexene is converted into a halfchair form. In this way a complete reaction mechanism with 8 to 10 rather than 3 reaction phases can be given.

April 2014

Marek is extending the reaction library by including curvature decomposition and reaction path decomposition plots. These together with the program of Hrant and Elfi have substantially improved the analysis.

March 2014

Dani works on the description of aromatic and antiaromatic molecules with the help of vibrational spectroscopy. He has found that the choice of the reference is essential for deciding between aromatic, non-aromatic, and antiaromatic systems. Furthermore, there is a need to distinguish between peripheral and ring specific delocalization in the case of polycyclic ring systems.

March 2014

Wenli, Michael, and Dieter work on an extension of the NESC program focusing on the 2-component NESC method. The target of this extension is to calculate response properties under consideration of spin-orbit coupling. The formulas are all developed in the first weeks of March. Michael had to leave but Wenli and Dieter are close to finishing the program.

March 2014

Directly after the conference the second URVA workshop took place in the CATCO group from March 5 to March 7. This time we focused on transition metal-catalyzed reactions with special emphasis on the catalytic activity of Au-, Rh-, and Pt-complexes.

March 2014

The 25th Austin-Dallas Symposium took place from March 1 until March 4. There were 108 participants from 22 different countries. 8 plenary talks, 60 invited lectures, and about 40 posters were presented in the 4 days of the Symposium. We had also to open a section after the dinner in the evening. The junior colleagues were given a chance of presenting their research results. The participants took all meals together so that ample time for discussions was available. The CATCO group presented its research by contributions of Dieter, Elfi, Marek, Wenli, Rob, Alan, Thomas, Dani, and Vytor.

February 2014

Congratulations to Alan (presenting), Wenli, and Dieter who obtained the Dean’s Departmental Award for their presentation of their research on long CC bonds on the occasion of SMU’s 2014 Research Day.
Research Day 2014

Dieter in discussion with Dean Quick at the Research Day.

February 2014

Wenli and Dieter have developed the local modes for van der Waals complexes. A complex made up from 2 monomers has just 6 intermonomer local modes, which are in some cases best described by using dummy atoms. Hence, the local mode program has to be extended to include also dummy atoms for the correct description of the six intermonomer local vibrational modes.

February 2014

January and February are the months of the annual reports and the new applications. The CATCO group looks back on an extremely busy year 2013, in which 20 papers were published, and a dozen presentations were given at national and international conferences all over the world.

January 2014

Vytor joins the group as graduate student. He comes from Brasilia and will work on catalytic reactions. He has quickly adapted to a completely new life style.

January 2014

Marek, Elfi, and Dieter are setting up the new reaction library, which will have a number of new features programmed by Wenli and Dieter. In the year 2014, the CATCO group will preferentially focus on catalytic reactions.

December 2013

Elfi and Dieter prepare the 25th Austin Symposium on Molecular Structure and Dynamics at Dallas (ASMD@D), which will take place celebrating the legacy of James E. Boggs. So far more than 70 internationally well-known scientists are in the list of speakers.

December 2013

Wenli and Dieter prepare the first public version of the local mode vibrational program. It is to become a stand-alone program that can be connected to various quantum chemical program packages.

December 2013

Dieter is working with Alberto and Jens on a two-pronged approach to determine the most stable conformers of medium-seized rings. Comparison of the measured and calculated rotational constants is the basis for the conformational analysis, which is non-trivial as pseudorotations, semiversions, and other interconversions between low-energy conformers take place in a 4-dimensional conformation space spanned by hypercylindrical or hyperspherical coordinates.

November 2013

Wenli and Dieter presented a talk with the title "Dancing Atoms" at the ACS-conference for Advances in Computational and Theoretical Chemistry, SWRM, November 16 – 19, 2013. The talk summarized their work on pseudo-Jahn-Teller systems. At the same conference, Elfi presented a talk with the title "Unusual molecular complexes resulting from pnicogen bonding."

November 2013

Rob is finishing his thesis, which is based on publications most of which are already printed. The thesis contains a summary of these publications in a short, generally understandable way and a long appendix containing the publications. We should in the future follow this example. It has the advantage that experts have already evaluated the papers and the quality of the thesis work can be assessed in an easier way.

November 2013

Wenli, Michael, and Dieter have summarized their method development work with the Diract-exact relativistic method NESC. By using the two-component NESC method in connection with coupled cluster theory, very reliable bond dissociation energies and reaction energies are obtained for molecules containing relativistic elements.

November 2013

Dani, Rob, Elfi, and Dieter have extended the investigation of aromatic and antiaromatic molecules using vibrational spectroscopy. They proved that with the help of vibrational properties the degree of pi-delocalization and by this also the degree of aromaticity or antiaromaticity can be quantitatively determined.

October 2013

Elfi visited the School of Pharmacy at the University of Minnesota and presented in an invited lecture on her recent work on non-toxic anticancer leads.

October 2013

Wenli and Dieter got the scalar curvature of the reaction path expressed in mass-weighted internal coordinates, however, still have to fight with numerical problems, i.e. numerically they get it right, but when using their analytical algorithm it comes out wrong. This should be solvable.

October 2013

Rob calculated a key energy parameter of H-bonding in acid dimers. This parameter is the basis for literally each methodology test focusing on H-bonds. It turned out that all previously published values are wrong by almost 20%, which is unusually large for the high-accuracy calculations previously carried out. However, Rob had to do CCSD(T)/CBS studies with quadruple and pentuple zeta basis sets to find this out.

September 2013

Rob, Elf and Dieter have finished their work on a revision and extension of the Tolman electronic parameter (TEP) for which they invented the Local TEP (LTEP). LTEPs express the Tolman electronic parameter in terms of local vibrational frequencies, which are much more reliable than the normally used normal mode frequencies. They found that the scattering of the TEP values is a result of the coupling of CO stretching modes with metal-carbon stretchings and carbon-metal-carbon bendings. LTEP values do no longer suffer from this, can be determined for any transition metal complex, and are directly available from measured or calculated spectra.

September 2013

Rob, Dani, Elfi, and Dieter are working on a new aromaticity index based on CC stretching modes. Rob’s work already shows that the larger stability of phenanthrene as compared to anthracene is a direct consequence of improved pi-delocalization. There are no stabilizing H,H interactions in the bay region of phenanthrene as was speculated in the literature. However, the space confinement of these CH bonds makes them stronger, which leads to an unusual new principle: bond strengthening caused by exchange repulsion.

September 2013

Wenli and Dieter worked out a way of determining the normal and local mode frequencies of isotopomers once the experimental frequencies are reliably known. Together with Rob and Elfi the 12 deuterium isotopomers of water were investigated according to a suggestion of Craig.

August 2013

Michael, Wenli, and Dieter presented their work on Dirac-exact relativistic methods at the VIIIth Congress of the International Society of Theoretical Chemical Physics, Budapest, Hungary. Elfi presented her work on chiral discrimination via local vibrational modes at this conference.

August 2013

Eric, Wenli, and Dieter are investigating BDT complexes with Cd and Pb ions. BDT complexes remove these toxic metals in form of a precipitate from aqueous solution. More and more evidence indicates that the precipitate contains acyclic oligomers of BDT-bound metal ions.

August 2013

Dieter, Wenli, and Michael are summarizing their method development work on Dirac-exact relativistic methods in a review article. Within a short period of somewhat more than 2 years the methodology and the programs for calculating a whole series of response properties has been developed and applied.

July 2013

Elfi gave a talk on Marek’s and her work on “Pnicogen bonding investigated with vibrational spectroscopy” at the 6th International Heron Island Conference on Reactive Intermediates and Unusual Molecules.

At the same conference, Dieter presented Wenli’s and his work on Jahn-Teller and pseudo Jahn-Teller surfaces calculated in terms of curvilinear coordinates. Title of the talk: "Molecules without structure – The Pseudo-Jahn-Teller Effect."

July 2013

Wenli and Dieter managed to obtain for the first time local vibrational modes for non-equilibrium situations. Their work means a major step forward to describe and understand the changes in the electronic structure of a reacting molecule.

July 2013

Marek, Zhanyong, and Dieter carry out large-scale ab initio calculations on small proteins. This is a long-term project, which should show whether modern QM/MM technology can correctly describe secondary and tertiary structure of proteins from scratch.

June 2013

Marek is studying the Ti-catalyzed Sharless epoxidation reaction using URVA. The problem is to model the bulky catalyst in a way that its reaction involvement can be monitored along the reaction path. This will require at least 800 path point calculations with gradient and Hessian at each point. A gigantic computational job if not a simpler presentation of the catalyst becomes possible.

June 2013

Elfi has started to modernize the webpage for the Austin Symposium at Dallas (ASAD). This is absolutely necessary for the 2014 ASAD meeting. Dieter has also started to modernize the reaction library so that the new results are presented in an easier way.

June 2013

Wenli and Dieter have finished the URVA program based on redundant coordinates. This provides an excellent basis to program the whole procedure in internal coordinates to have a basis for analyzing path direction and path curvature in terms of internal coordinate contributions. This is rather tricky and will keep them busy probably during the summer.

May 2013

Congratulations to Eric, who has just received the prestigious Goldwater Fellowship! Eric will be supported by the Goldwater Foundation during his senior year at SMU. In this time, he will carry out an environmental study focusing on removing heavy metals, including lead, cadmium, and mercury, from industrial wastewaters. Supervised by Dr. Dieter Cremer, Eric will use various relativistic programs developed by Wenli, Michael, and Dieter during the last two years at SMU, as well as the unitversity's newly acquired and improved computational facilities.

May 2013

Rob is working on the Tolman rule, which plays an important role in catalysis. He can show that this rule is misleading because it is based on the assumption that CO frequencies in transition metal carbonyls are independent of mode-mode coupling. There are large coupling effects! This means that the Toleman rule has to be reformulated and new insights into catalysis become possible.

May 2013

Wenli and Dieter are working on a new version of URVA, which will be able to use redundant or curvilinear coordinates. Their work is based on the idea that atoms move during a chemical reaction on curved paths, which are best described by curvilinear rather than rectangular (Cartesian) coordinates. One can simulate these movements also by sets of redundant coordinates. The Objective of the work is to avoid path instabilities when investigating catalytic reactions. Their work will be essential for the URVA analysis of complex reactions.

May 2013

Joao, Elfi, and Dieter are developing the potential energy surfaces of weak hydrogen-bonded complexes to determine exact rovibrational constants. The knowledge of these spectroscopic constants in connection with the local H-bond stretching modes will provide a much better insight into the nature of weak H-bonding.

May 2013

David’s experimental results verify what Wenli and Dieter had predicted on the basis of 77^Se NMR chemical shift calculations: Selenite reacts with the dithiol BDT to form cyclic selenosulfanes, which precipitate and can be removed by mechanical means from aqueous solutions. This provides a chance to purify wastewaters from steel mills or industries working with selenium.

May 2013

Marek, Thomas, Elfi, and Dieter concluded a study of 1,3-dipolar cycloadditions that has led to a multitude of new insights. Especially, Thomas’ approach to monitor the charge transfer from the 1,3-dipole to the dipolarophile was a success because it reveals that this kind of charge transfer is essential for the labilization of the dipolarophile and the formation of radicaloid centers between which the new bonds are established. The new insights help to understand the mechanism and the energetics of 1,3-dipolar cycloadditions at a level never reached before.

May 2013

Eric is working together with Wenli and Dieter on the atomization energies of actinide hexafluorides. His studies will answer the important question to which extend atomization energies depend on spin-orbit coupling (SOC) effects. It is also interesting that SOC also has some significant impact on the molecular geometry.

May 2013

Rob, Elfi, and Dieter are working on the question of what the strongest chemical bonds on this globe are. They have identified a number of candidates and can show that despite a large variety in the bond dissociation energies, there are several bonds that have bond orders of 3.3 bonds. They are working on the publication.

April 2013

Elfi presented a dinner talk at the local Duluth/Superior ACS section entitled: “What can we learn from Nature? Research connecting the in vivo with the in silicio world.” Students, faculty and guests were impressed how much chemistry can be explored with computers.

April 2013

Marek is working on catalytic cycles involving Au and Rh compounds. There is the necessity to find a new way of quantifying electronic structure changes at the transition metal atom. This can be done by generalizing the curvilinear coordinates Wenli and Dieter have developed for the description of bond pseudorotation.

April 2013

Zhanyong, Elfi and Dieter are setting up the helix analysis routines for general use on the CATCO web page after their paper has been accepted for publication in J. Mol. Model. With the help of Zhanyong’s program HAXIS, one can now easily and precisely define the secondary structure of a protein, an otherwise arduous task.

April 2013

On April 7, Elfi presented her research on computer assisted drug design to a group of STEMPREP 12th graders. This group of extremely talented high school students has been accepted to SMU under the early action program.

March 2013

Wenli and Dieter finished the analysis program for infrared intensities. This is based on the local mode intensities and the adiabatic connection scheme (ACS) between normal and local mode infrared intensities. In the case of equivalent local modes, the intensity-ACS is characterized by a catastrophe point, which helps to identify equivalent intensities in larger molecules. The intensity program reveals that H-bond stretching vibrations have large intensities, which are “dissipated” by mode-mode couplings.

March 2013

On March 21, Elfi represented the research of the CATCO group as a panelist at the Impact Symposium entitled: "The Power of predictions: Its promise as well as its limitation." The event was organized by the Dedman College Interdisciplinary Institute and the Richard B. Johnson Center for Economic Studies, supported by the Embry Family Foundation. Elfi presented that, with today’s computers, predictions can be made with the help of quantum chemical calculations, which are of extreme value for the design of new materials and medicinal drugs. Often quantum chemical calculations are more accurate than in experiment.

March 2013

On March 15, 2013, Dieter presented the J. W. Whalen Memorial Lecture at the University of Texas at El Paso (UTEP). He talked about "Bond curiosities throughout the periodic table."

March 2013

Elfi and Dieter wrote a review on the chemistry of the enediynes. Writing the review was a learning experience, because even as an expert one is always stunned how rapidly a topic can develop in such a short time. Enediynes are no longer a topic of just medicinal chemistry but also of organic synthesis, mechanistic chemistry, polymer chemistry, and material sciences.

March 2013

Alan and Dieter are working on pancake bonds. Typically these bonds are 3 Å and longer. Therefore the important question to be asked is whether these really are "chemical bonds." This extends to the question Alan has asked before: "What is the longest CC bond ever observed?"

February 2013

Dieter presented a seminar at TexTech University in Lubbock on February 22, 2013, entitled: "Mercury bonding described with relativistic quantum chemistry – Report on a serious discrepancy between theory and experiment."

February 2013

The spin-orbit coupling (SOC) program of Michael, Wenli, and Dieter works better than originally expected. SOC energy corrections come out very accurately and the orbital splittings caused by SOC match the most accurate calculations obtained with much more expensive methods.

February 2013

Alan and Dieter are close to solving the question of the long C1C6 bond in 11,11-Dimethyl-1,6-methano[10]annulene. It seems that this is a result of crystal packing. In the unit cell the molecules are stapled on top of each other pressing on the bridge atoms. This leads to a widening of the bridge angle and a closing of the 1,6-interaction from 2.2 down to 1.8 Å. Alan and Dieter plan to publish these results in honor of Emanuel Vogel who passed away last year.

February 2013

Rob has finished his study of the formic acid dimer using exclusively experimental vibrational frequencies. He shows that symmetric H-bonding in the cyclic dimer is almost 2 times stronger than the H-bond of the water dimer. He has identified the normal vibrational frequency that far-infrared specialists have measured to describe H-bonding. It is strongly reduced because of mode-mode coupling and does no longer describe the true nature of H-bonding. He, Elfi, and Dieter are writing a paper summarizing these results.

January 2013

Hrant and Elfi published in J. Comp. Theory Comp. their new version of the reaction path following algorithm for URVA studies which makes sure that the reaction path curvature is correctly calculated early in the entrance channel. There, the curvature of the reaction path indicates whether the electronic structure of the reaction complex is easily distorted or not. For example, the rotation at the ethylene bond or the rearrangement of HCN start with a high curvature.

January 2013

Wenli and Dieter are working on a new version of the ACS, which will start with lambda = 1. In this way, one can use symmetry and thus avoid a diabatic mode ordering. The reverse ACS diagrams will complement the information of the normal ACS diagrams. Any errors in the ordering of the vibrational eigenstates will promptly be corrected.

January 2013

Marek and Elfi are working on their second chirality paper, which focuses on large chiral complexes calculated with coupled cluster methods.

December 2012

CATCO Workshop 2012 (December 10 – December 14)

(Organized by Marek Freindorf, Wenli Zou, Robert Kalescky, Elfi Kraka, and Dieter Cremer, CATCO, Department of Chemistry SMU)
The following 8 quantum chemical programs were used (in alphabetical order)

CFOUR, DIRAC, GAMESS, GAUSSIAN, NWChem, MOLPRO, ORCA, and Q-Chem,

their input and output files discussed, and the following 25 methods applied for calculating
  • Ground state properties: SOS-RI-MP2, O2-SOS-MP2, local MP2, dual-basis-RI-MP2, RIJCOSX-SCS-MP2, parallel MP2, CCSD(T) with BSSE and thermochemistry, OD-CCD, ωB97X-2(LP), dual-basis-ωB97X
  • Excited states: CIS, CIS(D), TD-DFT, SF-DFT, EOM-CCSD, EOM-SF-CCSD
  • Multireference effects: CASSCF, CASPT2, CASPT3
  • Relativistic corrections: DKH2/CASSCF, DKH2/MR-CISD, SOC/CASSCF, 2-component SOC/ECP, 4-component DHF
  • Environmental effects: DFT/COSMO, DFT/PCM, FMO/RHF, EFP/RHF
Final exam on December 17, 2012 (written test with a total of 17 questions concerning the methods used in the workshop)

November 2012

Wenli, Michael, and Dieter worked on a two-component form of the NESC program. Objective is to calculate spin-orbit coupling (SOC) including the correct splitting of the molecular orbital energies. The new theory and the corresponding program were finished in November. The NESC/SOC data match the accuracy of Dirac 4-component calculations.

November 2012

A major problem with the adiabatic connection scheme is the occurrence of avoided crossings between degenerate vibrational eigenstates of different symmetry (which is obviously wrong). Wenli and Dieter worked out a procedure for rotating degenerate eigenvectors until the maximum overlap criteria have been fulfilled. Thus, the correct ordering of vibrational eigenstates is enforced.

October 2012

Dieter presented the local modes theory at the 2012 SWTCC conference at Texas A&M, October 26 – October 28, 2012. He gave a plenary talk entitled:
“Local Vibrational Modes: A New Tool to Describe the Electronic Structure of Molecules” (see CATCO presentations )
Elfi gave a talk entitled “The decisive role of H-bonds in chiral discrimination unraveled by quantum chemical means” at the 2012 SWTCC.

October 2012

Rob worked out a bar diagram that nicely reflects the composition of a normal vibrational mode in terms of local vibrational modes. We will routinely use these bar diagrams in the future when describing vibrational spectra.

October 2012

On October 1, 2012 Elfi Kraka presented a lecture entitled “How Chemistry can Learn from Nature: - A CADD Approach to Non-toxic Enediyne Anti-tumor Drugs” at the University of Brasilia, Brasilia, Brazil.

September 2012

On September 31, Dieter was invited by the Department of Physics, University of Brasilia to give a lecture entitled:
“Detailed Description of the Electronic Structure of Molecules and Chemical Bonding with Vibrational Modes” An interesting discussion about the possibilities of modern vibrational spectroscopy took place after the lecture.

September 2012

Elfi and Dieter attended the Symposium for “Electronic Structure and Molecular Dynamics, IV SEEDMOL” in Pirenopolis, Brazil, September 24 – 28 where they gave plenary lectures with the titles:
“Removal of toxic contaminants from the environment – A quantum chemical study with Dirac-exact relativistic theory” (Dieter)
“Hydrogen-Bonds in Homochiral and Heterochiral Compounds Distinguished by Vibrational Spectroscopy” (Elfi)

At the same conference, Elfi and Dieter, organized and presented a workshop on:
“A new Way of Understanding Chemical Reactions: The Unified Reaction Valley Approach” (6 lectures and 6 training sessions).

September 2012

The first CATCO workshop was presented. Topic was the Unified Reaction Valley Approach (URVA). In 5 days, all aspects of URVA were discussed. Contributions in form of lectures (Dieter) and in form of exercises were made by Dieter, Elfi, Marek, Thomas, Rob, Alan, Dani, and Wenli.

August 2012

On August 20, 2012 Elfi Kraka presented an invited talk entitled “The Unified Reaction Valley Approach: New insights into the mechanims of 1,3-Dipolar Cycloadditions” at the Special Symposium “Exploring Potential Energy Surfaces in Quantum Chemistry. A Tribute to H. Bernhard Schlegel” held at the 244th ACS National Meeting in Philadelphia, August 19-23, 2012.

August 2012

Paul and Elfi are writing up Paul's research in a paper. This is quite an accomplishment!

August 2012

Rob, Wenli, Elfi, and Dieter studied the water dimer at the highest level possible. They could proof that H-bonding is much stronger than suggested by a stretching frequency of just 140 cm-1. The local mode stretching frequency is at 520 cm-1. The reduction in the frequency is a result of mass coupling, avoided crossing, and anharmonicity effects. This result is essential for Elfi and Marek’s work on chirality.

August 2012

Wenli, Elfi, and Dieter are battling with the problem of getting free reaction energies as precicisely as possible in aqueous solution and to use these for pKa calculations. For smaller molecules the problem is solvable but for biomolecules it becomes a pain.

August 2012

Marek and Dieter found an interesting reaction mechanism for a polymerization problem suggested by Nick, in which trivalent and tetravalent iodine plays a central role.

August 2012

Wenli, and Dieter defined for the first time the intensities of the local vibrational modes. They extended the adiabatic connection schemes for the frequencies by one for the corresponding intensities. Knowing that the intensities are directly related to the atomic charges via the polar tensor, this is a much promising development. However the calculation of atomic charges from measured experimental frequencies via the local mode intensities will be a tough problem.

July 2012

Paul and Elfi studied substituted phosphine dimers and found that depending on the substituent there are relatively strong stabilizing interactions via the electron lone pairs although the latter should repel rather than attract each other. Analyzing local vibrational modes and the electron density distribution a surprising through-space stabilization mechanism emerges that leads to binding energies similar to those found for H-bonded complexes. The effect will be important for crystal engineering and polymer chemistry.

July 2012

Elfi and Dieter wrote up the results for the hydrogenation reactions: XH_n + H_2 --> XH_n+1 + H. X is varied through the periodic table including also heavy elements such as Bi or Pb. The curvature peaks for the chemical processes reflect the barriers of forward and backward direction quantitatively! The Hammond-Leffler postulate is verified for the first time on a quantitative basis. This shows the power of the URVA method.

July 2012

Michael, Wenli, and Dieter investigated differences in the nuclear volumes of Au isotopes. They described them via the nuclear quadrupole coupling constants and the so-called quadrupole anomaly using the NESC method in connection with Coupled Cluster theory. They predict that gold complexes are ideally suited for measuring the quadrupole anomaly and getting in this way information on the nuclear volume (we are talking here about a radius of 5.43 fm = 5.43 x 10^-15 meter!)

July 2012

Thomas has found a solution for generating snapshots along the reaction path much more efficiently than was previously done by Marek. He has programmed Avogadro with the help of Geoffrey Hutchinson. This will reduce the work to present and analyze URVA results tremendously.

July 2012

Alan is battling to describe the “longest CC” bond ever observed. This is the 1,6 bond of 1.8 Å in one of the substituted methano[10]annulenes. The work is done in honor of Professor Emanuel Vogel, who passed away last year. He was one of the supervisors of Dieter (see Dieter’s scientific tree). DFT, Coupled Cluster, Multireference CC, REKS, CASSCF, CASPT2 – no method can reproduce the X-ray geometry. The interaction distance seems to depend on environmental effects.

June 2012

Elfi presented her work (done together with Marek) on chirality at the Forth Worth International Chirality meeting. She investigated the question why biomolecules are preferentially homochiral rather than heterochiral. Utilizing the local modes and describing H-bonding, Elfi and Marek have an answer.

June 2012

This is the summer of writing up results. The number of publications submitted or written up extends largely what was done in the first two years. However the publications are largely a result of what has been done in the first years.

June 2012

Dani arrived. Dani has already some experience in REKS-DFT and TD-DFT, which he can bring in. He will use the adiabatic connection scheme to simplify the interpretation of vibrational spectra.

June 2012

Eric and Dieter finished the work on the actinidehexafluorides. Eric compared both the old NESC and the SMU-NESC method. The latter contrary to the former provides reliable results, which is very important when second order response properties are calculated.

June 2012

Marek and Elfi investigated the question how chiral molecules were formed in the early stages of this globe. Why are most biomolecules homochiral rather than heterochiral? Their answer is that chiral molecules are generated in the course of complex formations. They demonstrate that H-bonding plays an important role. By analyzing H-bonding they can predict the chirality of the complexes formed.

May 2012

Wenli and Dieter have found a second criterion how to get a unique force constant matrix for the Wilson FG formalism. The important result is that local mode force constants do not depend on the way Cartesian force constants are transformed into internal coordinate force constants.

May 2012

David, Wenli, and Dieter have found a way to detect Se in ppb concentrations, to complex it, and precipitate it. A paper is in preparation. David and Dieter have developed a project to extend the work for the investigation of arsenic in drinking water.

May 2012

Dieter gave a talk on the relativistic work and its application to environmental questions. It is a wonderful idea to hear what our colleagues in physics, math, and biology are doing.

April 2012

Dieter and David have joined forces for designing and synthesizing organic tweezers molecules suitable to remove contaminants from the environment. Dieter’s works focuses on mercury contaminations. Laboratory results suggest that organic tweezers can clean waters from Hg in a very efficient way.

March 2012

Dieter wrote a long review article on Configuration Interaction (CI) and Quadratic Configuration Interaction (QCI) theory. He described the various development steps of CI and the history of Pople’s QCI. He provided a balanced view on the scientific dispute between Pople and Paldus, the limitations of QCI, and how Zhi He and Dieter overcame these problems.

March 2012

Wenli and Dieter achieved another breakthrough by proofing that the local modes of Konkoli and Cremer are the true counterparts of the normal vibrational modes. The missing link between the two sets of force constants is the compliance matrix of Decius. Wenli and Dieter worked out the adiabatic connection schemes between normal and local modes. With the local modes and the adiabatic connection schemes Chemists have now a powerful tool in their hands to describe bonding, changes in bonding, and the reorganization of electronic structure during chemical reactions.

March 2012

Elfi and Dieter organized the 24. Austin Symposium on Molecular Structure and Dynamics at Dallas (ASMD@D). 80 participants from 18 different countries attended an exciting conference. Essential for the success was the fact that presentations, discussions, and lunches took place all at the same locality. The Texan hospitality and the organization were praised by the participants. Dean Quick and Dean Tsutsui provided essential support without the ASMD2D would not have been so successful. The CATCO group made an important step to increase the visibility of SMU at an international level.

February 2012

Wenli and Dieter proofed that the compliance constants of Decius are nothing else but the reciprocals of the local mode force constants of Decius. Rob and Elfi confirmed this for some 40 organic molecules by calculating the corresponding values. This is a huge step forward in the description of bonding.

February 2012

Michael, Wenli, and Dieter finished the work on nuclear contact densities, which enables the calculation of Mössbauer shifts. Mössbauer spectroscopy has an increasing importance in environmental chemistry because one can detect heavy metal contaminations down to the ppb range. The calculated Hg-Mössbauer shifts are in excellent agreement with the observed values.

January 2012

Michael, Wenli and Dieter worked out the relativistic corrections for hyperfine structure constants using the NESC methodology and programs they had worked out in 2011. The calculation of these constants for heavy metal means is an important step for the detection of contaminants in the environment using analytical means such as EPR.

January 2012

Wenli and Dieter finished the work on the cyclopentadienyl cation, which is a molecule without structure because the inherent Jahn-Teller effect. The C atoms perform circular motions, which lead to bond-pseudorotation. Thanks to the curvilinear coordinates of Dieter and Wenli, the bond-pseudorotation surface of four substituted cyclopentadienyl cations expanded in terms of curvilinear coordinates could be determined for the first time. The deformation coordinates reveal that the pseudo-Jahn-Teller effect is much more important for cyclopentadienyl cations than the Jahn-Teller effect.

December 2011

Over X-mas Elfi and Dieter wrote up the description of H-bonds with the help of local modes based on Marek’s calculations. The local H-bond stretching force constant turns out to be a reliable and useful descriptor of the H-bond strength. For the first time covalent and pure electrostatic H-bonds can be distinguished by combining the local mode properties with the Cremer-Kraka criteria for covalent bonds. This will be a powerful tool for the investigation of H-bonfs in biomolecules.

November 2011

Wenli, Michael, and Dieter developed additional ways of getting accurate second derivatives for the renormalization term and matrix U that connects the large and the pseudo-large component of the modified Dirac equation.

October 2011

Rob gave his research presentation. He could show that the stability of carbenium ions is effectively increased by Cl and F, but less by Br and I. He also described bonding in halonium ions and between carbon and chalcogen atoms. There is a stunning similarity in the bonding mechanism of CX and CE bonds. The pi-contributions become significantly weaker for the higher homologues.

October 2011

Michael demonstrated that the response theory for second order properties within relativistic theory can be elegantly formulated within NESC. The NESC second derivative program works accurately. Wenli wrote some 3000 lines of FTN coding for this purpose.

September 2011

Wenli, Michael, and Dieter worked out the second derivatives for the relativistic NESC method and programmed them within COLOGNE. To get the second order response properties on needs, besides the electronic states, also the positronic states of the Dirac equation contrary to some claims in the literature.

September 2011

Rob is finishing his work on CX bonding (X = F, Cl, Br, I).

August 2011

Elfi gave a talk on Anticancer Drugs at UTA.

August 2011

CATCO carried out the first workshop for high school students. From 9 am to 6 pm, students of the School of Science and Engineering, Yvonne A. Ewell Townview Magnet Center, Dallas, were introduced into quantum chemical calculations and quantum chemical research (see Time Schedule for Workshop).

August 2011

Wenli and Dieter finally solved the basic secret of the compliance constants: They can be related to local modes.

August 2011

Zhanyong, Elfi, and Dieter give the reaction library a new form.

August 2011

Marissa calculated the pseuorotational surface of adenosine and demonstrated the influence of H-bonding.

August 2011

Eric showed that picture change and finite nuclei have little influence on molecular properties of actinide hxafluorides such as geometry and vibrational frequencies, however a large influence on the energy.

July 2011

Dieter presented at the SimOC conference in Vigo, Spain, a talk on Reaction Mechanism.

July 2011

Elfi presented a talk on Reaction Design and the Formation of Allenylcarbene at the WATOC 2011, Santiago del Compostella, Spain.

July 2011

Dieter presented at the WATOC 2011, Santiago del Compostella, Spain, the work on the NESC energy gradients.

July 2011

Wenli derived an improved one-step solution of the Sylvester equation in connection with the NESC gradient.

June 2011

Elisabeth is investigating the conformational flexibility of cytidine.

June 2011

Wenli and Dieter published the basic paper on Jahn-Teller surfaces spanned by deformation coordinates.

May 2011

Wenli, Michael, and Dieter publish the new NESC algorithm and the analytical energy derivatives of the relativistic NESC equations; this leads to a big step forward in correctly calculating the molecular properties of molecules with heavy atoms, which is absolutely necessary for the catalytic studies of the CATCO group.

May 2011

Wenli and Dieter finished their work on deformation coordinates. For the first time Jahn-Teller surfaces and phenomena such as bond pseudorotation can be presented with a set of natural deformation coordinates in this way avoiding the tedious (and sometimes unsolvable) problems with normal coordinates. Bond pseudorotation in the cyclopropyl radical cation, cyclobutadiene, and other molecules was described.

April 2011

Zhanyong is working on the APSA program and webpage. The first paper is about to get finalized.

April 2011

Elfi has introduced the improved version of the URVA program that uses a larger step size but nevertheless resolves avoided crossings with the help of perturbation theory.

March 2011

Rob gave a group seminar on the basics of vibrational spectroscopy. View the Presentation.

March 2011

Eric has started to calculate uranium hexafluoride with high precision using NESC.

March 2011

The task of explaining the Z-E-isomerization of the indolin-2-ones suggested by Ed Biehl’s group turns out to become a major research project. The reaction proceeds in 7 hours at room temperature. How can rotation at an ethene-type double bond become so easy? Elfi and Dieter seem to have found the solution.

March 2011

Wenli, Michael, and Dieter have made a big step in getting relativistic corrections as accurate as a four-component Dirac description.

February 2011

Rob, Elfi, and Dieter are working on a new justification of the adiabatic vibrational modes. There is a chance to solve this problem once and for all.

November 2010

Wenli and Dieter managed to solve an important Jahn-Teller problem: How can one describe bond pseudorotation in cyclic systems such as the cyclopentadienyl cation or the cyclopropane radical cation. There is a lot of potential of extending their ideas to bond shifting in annulenes.



Other News:
ACS Prespac

Professors Elfi Kraka and Dieter Cremer have designed an anti-cancer drug model that could lead to safe, more effective cancer treatments. The design involves natural substances, called enediynes, produced by microorganisms found in Texan and Argentine soils that, after slight but crucial modification, target tumor cells rather than healthy ones.

They conducted the research with the assistance of a team of graduate students from all over the world during a longer time period.

"Often cancer patients suffer severely from cancer treatments based on chemotherapy," Kraka said. “This new drug model could potentially help numerous people avoid illnesses and potentially fatal health complications that stem from side-effects often accompanying other drug treatments."

Their research was published in the American Chemical Society’s Journal of Physical Chemistry B and is recognized by the organization as a potentially major breakthrough in cancer research.

The breakthrough that Professors Kraka and Cremer and their team have made could have a tremendous impact on the treatment of one of the most significant diseases of our times. There are very few homes that would not be affected by this potentially groundbreaking drug model as families across the country and throughout the world can claim a relative who has suffered from this terrible disease.

For years, scientists have investigated substances produced by microorganism that naturally occur in soil. “Microorganisms have learned for 2 billion years longer than we how to fight toxic bacteria and viruses and in this time they have developed compounds such as the enediynes. Enediynes are the masterpieces of natural ingenuity and share a common mechanism, namely to cut like a scissors through the DNA of a cell. ” Kraka points out. “We have to learn from nature, however not blindfolded, but adjust nature’s design to our needs.” The natural enediynes kill both cancer and healthy cells, which limits their effectiveness as anti-cancer drugs. Nevertheless, one has used for example in Japan enediynes already as antitumor drugs at the cost of serious side effects. “If a patients has no other choice, he or she will even take an otherwise toxic drug to stop cancer growth”, Kraka says.

The researchers learned through computer-assisted drug design that by combining enediynes with other substances called amidines also found in microorganism, they can form agents that target preferably acidic environments. Since cancer cells generate an acidic environment whereas normal cells have a slightly basic environment, only the cancer cells will be destroyed by these so called dynemicin-amidines (DADs) drug candidates.

Researchers are currently seeking pharmaceutical companies that would be interested in the design of the first nontoxic enediyne antitumor drugs based on the DAD principle.

Summary 2010
NSF Highlight