# Electron affinities of At and its homologous elements Cl, Br, and I

## TL;DR

This study uses advanced quantum calculations to accurately predict the electron affinity of astatine, comparing well with experimental data for other halogens, and improves theoretical predictions significantly.

## Contribution

The paper applies a multiconfiguration Dirac-Hartree-Fock method to predict electron affinities, achieving unprecedented accuracy for halogens including astatine.

## Key findings

- Predicted electron affinity of At: 2.3729(46) eV.
- Achieved <0.2% agreement with experimental data for Cl, Br, I.
- Significantly improved theoretical predictions over previous studies.

## Abstract

The multiconfiguration Dirac-Hartree-Fock method is applied to study the electron affinities of At and its homologous elements Cl, Br, and I. Our method of calculation is validated through the comparison with the available experimental electron affinities of Cl, Br, I, and other theoretical values. The agreement between our predicted electron affinities and the available experimental values for Cl, Br, and I is within 0.2%, which is an improvement of more than a factor of 10 over previous theoretical studies. Applying the same method to At, the electron affinity of At is predicted to be 2.3729(46) eV.