Eur. Phys. J. D (2021) 75: 123
https://doi.org/10.1140/epjd/s10053-021-00040-8

Regular Article - Topical Issue

Ground and excited states of confined lithium atom using variational Monte Carlo Method

¹ Mathematics Department, Faculty of Science, Alexandria University, Alexandria, Egypt
² Mathematics Department, Faculty of Science, Menofia University, Shebin El-Kom, Egypt
³ Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt

^a sbdoma@alexu.edu.eg

Received: 6 September 2020
Accepted: 4 January 2021
Published online: 12 April 2021

Abstract

Electronic structures of the ground and the low-lying excited states of lithium atom confined by a hard prolate spheroidal cavity are investigated using variational Monte Carlo method. The effect of compression is studied in detail for a wide range of spherical box radius $r_c$. Our calculations are based on using an accurate few-parameter ground-state trial wave function associated with a cutoff factor, which was put forward in calculating ground-state energy in free case. This wave function is modified to study low lying excited states of lithium atom. The crossover of the ground-state configuration to $1{\text{s}}^{2}2\text{p}$ state is illustrated graphically. The obtained results exhibit good accuracy compared with the high-precision variational data presented previously.