Spectroscopic data for the LiH molecule from pseudopotential quantum Monte Carlo calculations

TL;DR

This paper uses quantum Monte Carlo methods to evaluate pseudopotential models of LiH, comparing calculated spectroscopic constants with experimental data to assess the accuracy of different pseudopotentials and core polarization effects.

Contribution

It provides a detailed analysis of pseudopotential models for LiH, highlighting the importance of core-valence correlation and core relaxation in accurate interatomic potential calculations.

Findings

Two pseudopotentials tested with good agreement to experimental data

Core polarization significantly affects interatomic potential accuracy

Errors are primarily due to pseudopotentials and core polarization assumptions

Abstract

Quantum Monte Carlo and quantum chemistry techniques are used to investigate pseudopotential models of the lithium hydride (LiH) molecule. Interatomic potentials are calculated and tested by comparing with the experimental spectroscopic constants and well depth. Two recently-developed pseudopotentials are tested, and the effects of introducing a Li core polarization potential are investigated. The calculations are sufficiently accurate to isolate the errors from the pseudopotentials and core polarization potential. Core-valence correlation and core relaxation are found to be important in determining the interatomic potential.