Two-band second moment model and an interatomic potential for caesium

TL;DR

This paper introduces a semi-empirical interatomic potential for caesium based on a two-band second moment model, enabling efficient large-scale molecular dynamics simulations of volume collapse transitions.

Contribution

It develops a novel two-band extension of the Finnis-Sinclair model tailored for materials like caesium, with parameters derived and tested for practical use.

Findings

Potential suitable for large-scale molecular dynamics

Parameters successfully derived for caesium

Model captures volume collapse behavior

Abstract

A semi-empirical formalism is presented for deriving interatomic potentials for materials such as caesium or cerium which exhibit volume collapse phase transitions. It is based on the Finnis-Sinclair second moment tight binding approach, but incorporates two independent bands on each atom. The potential is cast in a form suitable for large-scale molecular dynamics, the computational cost being the evaluation of short ranged pair potentials. Parameters for a model potential for caesium are derived and tested.