Projector Monte Carlo method based on Slater determinants: a new sampling method for singlet state calculations

摘要

A new sampling method is proposed for projector Monte Carlo (PMC) calculations based on Slater determinants (SD) in singlet states. Using the symmetry of the α and β electron determinants, the number of configurations to be considered can be about one-half of the original sampling. We applied the new sampling to the PMC-SD calculations of the H2O molecule in the ground state. The results were always improved by the new sampling method both for the equilibrium and for bond-stretched structures.