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Session B23 - DCMP: MONTE CARLO AND OTHER RANDOM METHODS
mixed session, Monday morning, March 20, 11:00
Room F, San Jose Convention Center
We are using the variance minimization method C.J. Umrigar, K.G. Wilson and J.W. Wilkins, Phys. Rev. Lett. 60, 1719 (1988). to determine accurate wavefunctions for first-row diatomic molecules. The form of the wavefunction is a product of a sum of determinants and a generalized treat molecules) which has been shown to give accurate wavefunctions for atoms. One of the important features of the calculations is that we are systematically including all determinants that can be formed using orbitals with principal quantum numbers that do not exceed those occurring in the Hartree Fock configuration. The idea is that the near-degeneracy correlation is most effectively described by a linear combination of low-lying determinants whereas the dynamic correlation is well described by the generalized Jastrow function. All the parameters occuring in both the determinantal and the Jastrow parts of the wavefunction are optimized; in all typically 100 parameters of five different kinds. The optimized wavefunctions are used in both Metropolis and diffusion Monte Carlo calculations. \noindent This work is supported by the Office of Naval Research.
