Title: Self-Interaction-Free Exchange-Correlation Energy Functional for Thermodynamics and Kinetics

Speaker: Weitao Yang, Duke University

Date/Time: Thursday, November 9, 2006, 3:00 - 4:00 pm

Location: CSRI Building, Room 279 (Sandia NM)

Brief Abstract: The self-interaction error is undoubtedly the origin of many qualitative and quantitative failures which plague DFT.  Some of these are dissociation of molecules and radicals, treatment of fractional number of electrons and charge transfer processes, underestimation of reaction barriers and over estimation of polarizabilities. Orbital or potential functionals provides the key to address this problem. We develop a self-interaction-free exchange-correlation functional which is very accurate for thermochemistry and kinetics. This is achieved by theoretical construction of the functional form and non-linear fitting. We define a simple interpolation of the adiabatic connection that uses exact exchange, generalized gradient approximation (GGA) and meta-GGA functionals. The performance is optimized by fitting a small number of empirical parameters. Overall the functional improves significantly upon functionals such as BLYP, and B3LYP in many different tests, while correctly describing one electron systems, having exchange-correlation potential with accurate long-range behavior, and being also size extensive.  The mean absolute error on a large set of reaction energy barriers is reduced to 1.99 kcal/mol, representing a significant advance beyond the widely used hybrid functionals. 

CSRI POC: Rick Muller, (505) 284-3669