Eur. Phys. J. Spec. Top.
https://doi.org/10.1140/epjs/s11734-026-02352-5

Regular Article

Interatomic Coulombic decay initiated by electron removal and excitation processes in argon dimers subjected to helium ion impact

Department of Physics and Astronomy, York University, M3J 1P3, Toronto, ON, Canada

^a This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 19 February 2026
Accepted: 24 April 2026
Published online: 15 May 2026

Abstract

The electron removal and excitation channels that facilitate interatomic Coulombic decay (ICD) in argon dimers subjected to helium ion impact are investigated. We implement an independent-atom and independent-electron model of the collision system with the dimer target fixed at its equilibrium bond length and the He$_{}^{2+}$ and He$_{}^{+}$ ion projectiles traveling parallel to the dimer axis at impact energies ranging from 10 keV/amu to 150 keV/amu. The coupled-channel two-center basis generator method for orbital propagation is used within both a frozen atomic target approximation and a dynamic response framework. Given that ICD is facilitated through electron excitation pathways in argon dimers, a statistical technique called determinantal analysis is employed to investigate these channels. The analysis is further subdivided into models that exclude and include projectile charge changes during the collision. Electron configurations of the form Ar$_{}^{+}$($3p^{-2}nl$) offer a pathway to ICD and are investigated, along with other one- and two-electron removal channels that lead to Ar$_{}^{+}$-Ar$_{}^{+}$ fragmentation. We find that the 3d excited state is an overall dominant channel for ICD with other excited states ranging from 4s–4f also being significant contributors. Our study notes differences between static and dynamical potential models across the projectile impact energy range, though of decreasing significance as the impact energy approaches 150 keV/amu. We also find that a He$_{}^{+}$ projectile offers a strong pathway for ICD as the projectile impact energy decreases.