Quantum Monte Carlo with Jastrow-valence-bond wave functions

TL;DR

This paper explores the use of Jastrow-Valence-Bond wave functions in quantum Monte Carlo methods, demonstrating their effectiveness in accurately modeling electron correlation in diatomic molecules.

Contribution

It introduces a new approach combining valence bond wave functions with Jastrow factors for improved quantum Monte Carlo calculations.

Findings

Accurate equilibrium well depths for C₂, N₂, O₂, and F₂ molecules.

Compact wave functions effectively describe static and dynamic electron correlation.

Systematic improvement possible by adding more valence bond structures.

Abstract

We consider the use in quantum Monte Carlo calculations of two types of valence bond wave functions based on strictly localized active orbitals, namely valence bond self-consistent-field (VBSCF) and breathing-orbital valence bond (BOVB) wave functions. Complemented by a Jastrow factor, these Jastrow-Valence-Bond wave functions are tested by computing the equilibrium well depths of the four diatomic molecules C$_2$, N$_2$, O$_2$, and F$_2$ in both variational Monte Carlo (VMC) and diffusion Monte Carlo (DMC). We show that it is possible to design compact wave functions based on chemical grounds that are capable of describing both static and dynamic electron correlation. These wave functions can be systematically improved by inclusion of valence bond structures corresponding to additional bonding patterns.