New Density Functionals: A Meta GGA and Three Hybrid Meta GGAs with Good Performance for Thermochemistry, Thermochemical Kinetics, Noncovalent Interactions, and Spectroscopy

Friday, August 3, 2007 - 11:00am - 11:30am
EE/CS 3-180
Donald Truhlar (University of Minnesota, Twin Cities)
In work carried out with Yan Zhao, we have developed a suite of hybrid meta exchange-correlation functionals, including three hybrid meta generalized gradient approximations (hybrid meta GGAs) called M06, M06-2X, and M06-HF and one local meta GGA, called M06-L. The M06 and M06-L functionals are parametrized including both transition metals and nonmetals, whereas the M06-2X and M06-HF functionals are high-nonlocality functionals with double the amount of nonlocal exchange (2X) as compared to M06 and 100% Hartree-Fock exchange, respectively, and they are parametrized only for nonmetals. We have assessed these four functionals by comparing their performance to that of other functionals and other theoretical results for 403 accurate energetic data in 29 diverse databases, including ten databases for thermochemistry, four databases for kinetics, eight databases for noncovalent interactions, three databases for transition metal bonding, one database for metal atom excitation energies, and three databases for molecular excitation energies. We have also tested the performance of these 17 methods for three databases containing 40 bond lengths and for databases containing 38 vibrational frequencies and 15 vibrational zero point energies. We recommend the M06-2X functional for applications involving main-group thermochemistry, kinetics, noncovalent interactions, and electronic excitation energies to valence and Rydberg states. We recommend the M06 functional for applications in organometallic and inorganometallic chemistry and for noncovalent interactions. We recommend the M06-HF functional for all main-group spectroscopy, and we recommend the local M06-L functional for calculations on large systems, where a local functional is very cost efficient. An overview of this work will be presented.