Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 49: Ab-initio approaches to excitations in condensed matter II

O 49.11: Talk

Thursday, March 26, 2009, 13:00–13:15, SCH 251

Reduction of the number of orbital products and computation of molecular spectra from the Gross-Petersilka-Grabo equation — •Dietrich Foerster and Peter Koval — CPMOH, Universite de Bordeaux 1, 351 cours de la Libération , 33405 Talence, France

Electronic excitations in molecular systems live in a space of orbital products the dimension of which is too large for effective computation.

To circumvent this well known difficulty, we identify a smaller subspace of linearly independent "dominant directions" that span the original space of products with exponential accuracy.

As a first application, we compute molecular spectra by solving, in this subspace of reduced dimensions, the Gross-Petersilka-Grabo equations rather than the equations of Casida.

Possible applications of our method include the study of excitons in molecular systems.

Reference: D. Foerster, "Elimination, in electronic structure calculations, of redundant orbital products", J. Chem. Phys. 128 (2008) 43108.