Damped-Core Quantum Monte Carlo Method: Effective Treatment for Large-ZSystems

Abstract

A quantum Monte Carlo simulation method is introduced which treats core and valence electrons separately. This greatly minimizes problems associated with the very different energy and time scales present even at a moderate atomic number. The core is treated variationally by Metropolis sampling of a trial wave function, while the chemically important valence region is treated by a quantum Monte Carlo algorithm that solves the Schrödinger equation. We calculate ionization potentials and electron affinities of C, Si, and Ge, and find excellent agreement with experiment. Effective speedup over standard quantum Monte Carlo approaches is estimated to be as large as a factor of 5000.