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Monday, May 11, 2009
3:00 PM - 4:00 PM
CNLS Conference Room (TA-3, Bldg 1690)


Local hybrid: Fourth rung on the ladder of density functional approximations

John Perdew
Tulane University

Kohn-Sham density functional theory delivers the ground-state energy and electron density of a many-electron system from the selfconsistent solution of one-electron Schroedinger equations. Only the density functional for the exchange-correlation energy needs to be approximated. The standard approximations are single integrals over three-dimensional space of an energy density. On the ladder of approximations, the first three rungs (local spin density approximation, generalized gradient approximation or GGA, and meta-GGA) are semilocal, constructing this energy density from the local electron density, its gradient, and the positive orbital kinetic energy density. The fourth rung is truly nonlocal, employing also the exact exchange energy density. The success of the global hybrid functionals suggests a local hybrid in which the fraction of exact exchange mixed with semilocal exchange is a function of position and a functional of the density, chosen to satisfy many known exact constraints [1]. Progress beyond Ref. [1] will be discussed. It appears that local hybrid functionals can correct all of the one-electron and much of the many-electron self-interaction error of a good semilocal functional [2], at an increased but still acceptable computational cost. [1] J.P. Perdew, V.N. Staroverov, J. Tao, and G.E. Scuseria, Density Functional with Full Exact Exchange, Balanced Nonlocality of Correlation, and Constraint Satisfaction, Phys. Rev. A 78, 052513 (2008). [2] J.P. Perdew, A. Ruzsinszky, G.I. Csonka, L.A. Constantin, and J. Sun, Workhorse Semilocal Density Functional for Condensed Matter Physics and Quantum Chemistry, submitted.

About the speaker: Dr. Perdew is a world-leading researcher in electronic structure theory. He has made significant contributions to the development of density functional theory and has been listed as one of the most-cited physicists by ISI. One of his papers (PRL 1996) is the most-cited physics paper since 1994 and another (PRB 1980) has been ranked among the top 3 most-cited articles in the Physical Review family of journals since 1893. In 1998, Professor Walker Kohn cited Dr. Perdew's work in his Nobel prize speech. Several density functionals that Dr. Perdew developed have become the standard methods in electronic structure calculation and have been implemented in standard computer codes. He has co-authored over 230 research papers. He is a member of the International Academy of Quantum Molecular Science. In honor of his scientific accomplishments, the Journal of Chemical Theory and Computation published the Perdew special issue, which appeared in April 2009.

Dr. Perdew will visit Los Alamos from 5/10 to 5/15 (before 10:am). If you would like to talk with him, please contact Dr. Jianmin Tao (T-4/CNLS) at or 667-6840.

Host: Jianmin Tao, T-4/CNLS