An accurate few-parameter ground state wave function for the Lithium atom

TL;DR

This paper introduces a simple seven-parameter trial wave function for the Lithium atom's ground state, achieving accurate energy and expectation values through numerical integration.

Contribution

A novel, minimal-parameter wave function for Lithium's ground state that includes both spin functions and uses numerical integration for matrix elements.

Findings

Accurate ground state energy for Lithium

Correct cusp parameters achieved

Reliable expectation values obtained

Abstract

A simple, seven-parameter trial function is proposed for a description of the ground state of the Lithium atom. It includes both spin functions. Inter-electronic distances appear in exponential form as well as in a pre-exponential factor, and the necessary energy matrix elements are evaluated by numerical integration in the space of the relative coordinates. Encouragingly accurate values of the energy and the cusp parameters as well as for some expectation values are obtained.