Atoms in boxes: from confined atoms to electron-atom scattering

TL;DR

This paper introduces a unified basis set method to describe both confined atoms and electron-atom scattering, enabling calculations of atomic properties under confinement and scattering phase shifts within a consistent framework.

Contribution

The paper presents a novel basis set approach that unifies the treatment of confined atoms and scattering, including correlation effects via time-dependent density-functional theory.

Findings

First confined atom polarizability calculations including correlation.

Accurate scattering phase shifts for e-H and e-He+ obtained.

Method yields results consistent with previous scattering studies.

Abstract

We show that both confined atoms and electron-atom scattering can be described by a unified basis set method. The central idea behind this method is to place the atom inside a hard potential sphere, enforced by a standard Slater type basis set multiplied by a cutoff factor. For confined atoms, where the wall is placed close to the atomic nucleus, we show how the energy of the highest occupied atomic orbital and the static polarizability of helium and neon atoms evolve with the confinement radius. To our knowledge, these are the first confined atom polarizability calculations that include correlation, through the use of time-dependent density-functional theory. By placing the atom in a large spherical box, with a wall outside the electron density, we obtain scattering phase shifts using a recently developed method [M. van Faassen, A. Wasserman, E. Engel, F. Zhang, and K. Burke, Phys. Rev. Lett. {\bf 99}, 043005 (2007)]. We show that the basis set method gives identical results to previously obtained phase shifts for $e$-H and $e$-He${}^{+}$ scattering.