Correlated geminal wave function for molecules: An efficient resonating valence bond approach
Abstract
We show that a simple correlated wave function, obtained by applying a Jastrow correlation term to an antisymmetrized geminal power, based upon singlet pairs between electrons, is particularly suited for describing the electronic structure of molecules, yielding a large amount of the correlation energy. The remarkable feature of this approach is that, in principle, several resonating valence bonds can be dealt simultaneously with a single determinant, at a computational cost growing with the number of electrons similar to more conventional methods, such as HartreeFock or density functional theory. Moreover we describe an extension of the stochastic reconfiguration method, which was recently introduced for the energy minimization of simple atomic wave functions. Within this extension the atomic positions can be considered as further variational parameters, which can be optimized together with the remaining ones. The method is applied to several molecules from Li_{2} to benzene by obtaining total energies, bond lengths and binding energies comparable with much more demanding multiconfiguration schemes.
 Publication:

Journal of Chemical Physics
 Pub Date:
 October 2004
 DOI:
 10.1063/1.1794632
 arXiv:
 arXiv:condmat/0409644
 Bibcode:
 2004JChPh.121.7110C
 Keywords:

 31.25.v;
 31.15.Rh;
 33.15.Bh;
 31.15.Ne;
 31.15.Ew;
 33.15.Dj;
 33.15.Ry;
 Electron correlation calculations for atoms and molecules;
 Valence bond calculations;
 General molecular conformation and symmetry;
 stereochemistry;
 Selfconsistentfield methods;
 Densityfunctional theory;
 Interatomic distances and angles;
 Ionization potentials electron affinities molecular core binding energy;
 Condensed Matter  Other
 EPrint:
 20 pages, 5 figures, to be published in the Journal of Chemical Physics