Charge Exchange of Highly Charged Ions in 2D Materials

Abstract

Highly charged ions (HCIs) carry large amounts of potential energy, e.g., ~40keV for a Xe40+ ion, which results from the sum of binding energies of all removed electrons. Transmission experiments with 2D materials revealed that one layer of material can already be enough for complete neutralisation and deposition of this potential energy. The driving force behind this ultrafast deexcitation is the interatomic Coulombic decay (ICD), a distance-dependent Auger process, which is highly efficient at the small interatomic separations occurring during HCI-surface transmission [1]. Here we present a study of the neutralisation dynamics of HCIs in single-, bi-, and trilayer graphene samples by analysing the charge state of the ion after transmission for various kinetic energies and charge states. The results indicate that the neutralisation depends solely on the interaction time the ions spend in close proximity to the material layers [2]. Together with a simulation package modelling the HCI deexcitation via ICD [3], we establish a conceptual framework of ion deexcitation close to target atoms. As a conclusion, we apply this established knowledge to study amorphous organic nanosheets, which are challenging to characterise with traditional experimental techniques [4]. [1] R.A. Wilhelm et al. Phys. Rev. Lett. 119 103401 (2017) [2] A. Niggas et al. Commun. Phys. 4 180 (2021) [3] R.A. Wilhelm and P.L. Grande Commun. Phys. 2 89 (2019) [4] R.A. Wilhelm et al. J. Phys. Conf. Ser. 1412 062010 (2020)