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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
Quantum Monte Carlo calculations of electronic structure describe non-dynamic and dynamic correlations respectively by multiple determinants and Jastrow factors. The latter used to date correlate at most three particles. Here, we include many-body effects of higher order. Jastrow factors depend on polynomials in inter-particle distances, but the number of monomials grows rapidly with both degree and particle number, rendering computations for atoms or molecules expensive if polynomial order or Z is high. We design efficient algorithms using the theory of invariants M.P.Nightingale, J. Chem. Phys. 101, 8831 (1994) to exploit that the number of independent coefficients of polynomials with the correct particle-exchange symmetry grows more slowly than the number of monomials: instead of special polynomials in which the coefficients satisfy conditions imposed by this symmetry, we use \it general polynomials in a finite set of basic invariants. Our algorithm has the feature that the same set of basis invariants can be used for any atom or molecule. In addition, the number of free parameters to be optimized can be reduced considerably by imposing the cusp conditions exactly. This work is supported by ONR and the NSF.
