
Prof. Dr. Stefan Grimme
Method Development
(references also include examples of application)

Developement of the DFTD3 method and its precursors (now called DFTD1 and DFTD2). Although the 'dispersionproblem' in DFT was wellknown since about 15 years and DFTDtype methods had been proposed by others, it could be shown in 2004 for the first time that the approach solves the problem in a rather general way and that the correction can be coupled in a simple form to standard density functionals. The in 2010 proposed DFTD3 method includes several new ideas to make it less empirical and more accurate and to extend it consistently to the whole periodic table. It is just now replacing DFTD2 as the worldwide defacto standard in dispersion corrected DFT calculations. The B97D functional from 2006 was the first GGA that incorporates dispersion terms from the very beginning. DFTD3 and B97D have been implemented in all major codes. The two latest DFTD versions are meanwhile also used routinely in periodic solidstate calculations. It opens completely new possibilities for the application of DFT in the areas of condensed matter, materials science or biochemistry where dispersion effects are often of utmost importance.
Refs.[102,125,126,141,144,150,182,229,230,236,247,248,249,252]

Evaluation and improvement of densitybased dispersion corrections of nonlocal (NL) vdWDF type. First applications of this method to typical thermochemical problems and applications with hybrid functionals are conducted (termed DFTNL). Such methods can be used complementary to DFTD3 in many applications. The VydrovvanVoorhis functional VV10 has been adapted to standard density functionals and implemented selfconsistently into ORCA.
Refs.[261, JCTC in press]

Doublehybrid density functionals (DHDF) were proposed in 2006. DHDFs represent the fifth (highest) class of current density functionals and include nonlocal correlation effects and employ information about virtual KohnSham orbitals. The first developed functional B2PLYP (2006) at that time was the most general and most accurate DFT method for general chemistry applications to molecules and has meanwhile been implemented in all major quantum chemistry codes. It can be considered as the 'true' successor of the popular B3LYP functional. Many B2PLYP clones have been proposed since then and this has stimulated a lot of research activity on nonlocal correlation functionals of related RPA type.
Refs.[131,139,153,156,228,244]

Together with F. Neese the TDDHDF method was developed which extends DHDFs to the area of excited states. For example TDB2PLYP is currently the most accurate DF method for lowlying excitations in main group systems. It provides unprecedented accuracy e.g. for large unsaturated chromophores for which standard TDDFT often yields qualitatively wrong results (e.g. state orderings).
Refs.[164,188,197,206,264]

The SCSMP2 electronic structure method was proposed in 2003. It increases the accuracy of MP2 significantly at no additional computational overhead. It has become a standard tool in computational chemistry and is now implemented in all major program packages. The general spincomponent scaling (SCS) idea opened a new field in quantum chemistry and meanwhile many followup methods have been reported by researchers worldwide (e.g. SCSCCSD, SCSCC2, SCSCIS(D), S2MP2, SCS(MI)MP2, SOSMP2).
Refs.[86,92,93,100,101,105,106,113,119,133,155,216,233]

Development of MP2.5 which is a scaled variant of thirdorder MP perturbation theory for the computation of accurate noncovalent interaction energies (together with the group of P. Hobza). Estimated MP2.5/CBS energies very closely approach the accuracy of the current goldstandard CCSD(T) but can be evaluated for much larger systems with about 100 atoms routinely.
Refs.[196,214]

Simplified multireference perturbation methods (MRMPn) and a corresponding computer program using RI for large systems have been developed.
Refs.[54,61,71,73]

Its successor is the DFT/MRCI method (1999) which still represents one of the rare DFT methods for multireference (MR) cases. It is used by several research groups (e.g. Christel Marian at the University Düsseldorf) to routinely compute excited state properties of large molecules with DFT. The method partially solves the 'doubleexcitation' problem in TDDFT which is relevant for many important chromophores. The corresponding computer code represents the first implementation of the efficient RIapproximation for CI and MRMP calculations.
Refs.: [49,53,62,63,78,198]

The DFT/SCI method was at the time of its development (1996) the only generally applicable DFT method to routinely compute electronic spectra (UV and CD) of molecules. It turned out to be similar to the later developed TDADFT method of M. HeadGordon.
Refs.: [22,28,30,31,32,35,38,43,48]

Quantum chemical calculations of CDspectra and optical rotations (OR) for the assignment of the absolute configuration of molecules were established in the 90s. Various methods (semiempirical, CI, DFT) have been used. Work along the same lines was done later by P. J. Stephens (with more emphasis on OR). One of the first TDDFT calculations of OR also using RI techniques have been undertaken. The first electronic wave function based continuous symmetry measure (similar in application to D. Avnir's classical measure) has been developed in 1995 for the analysis of chiral systems.
Refs.[7,14,15,20,30,32,36,39,55,64,67,70,74,83,145,187]

A general intermolecular forcefield based on monomer (semiempirical) quantum chemical information (VDW3) has been developed. It is based on DFTD3 and will be used in the future in a QM/MM context for the improved description of e. g. solvent effects. A first application for computing adsorption isotherms of small molecules in porous materials by by GCMC simulations demonstrates the accuracy of the method.
Refs.[JPC C, submitted]

GridComputing: QMC@HOME as implemented in Münster in 2007 was the first worldwide established grid (cloud) computing project in quantum chemistry with currently > 15000 participants. It was developed originally for electronic diffusion quantum MonteCarlo (DMC) calculations but is meanwhile used more and more for large scale DFT calculations using the ORCA quantumchemical program (e.g. for sampling the conformational space of large bioorganic molecules).
Refs.[177,266,267]
Recent Applications and Computational Chemistry

Noncovalent interactions in large molecules, complexes and condensed matter systems, stacking interactions. Analysis and nonadditive contributions.
Refs.[121,127,157,171,177,180,182,185,209,234,235,236]

London dispersion effects for thermochemistry and intramolecular dispersion.
Refs.[100,130,173,195,204,229,232,262]

Thermochemical benchmarking (development of benchmark sets and calculation of accurate reference data).
Refs.[119,202,203,223,232,243,244,245]

DNA fragments, peptides and proteins.
Refs.[144,177,185,182,183,266]

Theoretical conformational analysis and assignment of absolute configuration of chiral molecules by theoretical OR and CD.
Refs.[134,145,161,167,187,188,190,242,226]

Theoretical description of socalled frustrated Lewis pairs (FLPs) and their reactions, which is currently one of the 'hottest' topics in synthetic chemistry (e.g. for H_{2} or CO_{2} activation).
Refs.[170,211,213,224,227,241,246,257,258,259,260]

Computional chemistry for organic transition metal complexes.
Refs.[104,114,160,166,184,204,222,262]

Analysis and interpretation of correlation effects in prototypical organic molecules (e.g. alkanes and aromatics) with special attention to DFT failures.
Refs.[105,152,135,149,192,199]

Excited electronic states and UV spectra.
Ref.[103,105,107,120,148,164,175,206,233]
Current Research Projects and Perspectives

Development of dispersioncorrected density functionals (DFTD3) with improved performance and reduced selfinteraction error which is a fundamental problem in DFT.

Development of very accurate hybrid and doublehybrid functionals with improved performance and broader range of application (using e.g. RPA).

Development of simplified (semiempirical) quantumchemical methods for about 10000 atoms (bioorganic systems).

Investigation of quantumchemistry based drugligand 'scoring' functions.

Application of dispersioncorrected DFT to surface (adsorption and reaction) and liquid phase problems (e.g., phase demixing in combination with MonteCarlo techniques).

Further development of extensive thermochemical benchmark sets and detailed assessment of electronic structure methods.

Theoretical investigation of chemical activation of small molecules. The work on FLP chemistry will be continued in close collaboration with the G. Erker and D. Stephan groups. In this context we have developed an electric field model of activation which might help to discover entirely new reactions.

Exploration of chemical reaction mechanisms and spectroscopic problems in close collaboration with experimentalists.

Investigation of nonadditive (cooperative) effects in noncovalent interactions. This work is strongly related to the SFB 858.

Further exploration of the recently introduced new concept of 'dispersion energy donors', i.e., functional chemical groups that stabilize certain structure or bonding situations by dispersion interactions. This might eventually lead to additional design principles for e.g. (stereoselective) catalysts.

