Multiple ionization state of Arq+ ions during collisions near the Bohr velocity

Xianming Zhou,Xinwen Ma,Yongtao Zhao,Yuyu Wang,Yanhong Chen,Rui Cheng,Yu Lei,Guoqing Xiao

doi:10.1038/s41598-019-41709-w

Xianming Zhou, Xinwen Ma + Show 6 more

Open Access

https://doi.org/10.1038/s41598-019-41709-w

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Abstract

In order to clarify the mechanism and the influence of the initial charge state and target atomic parameters for the formation of L-shell multiple ionization state of Arq+ ions produced by the collisions near the Bohr velocity, the k-shell x-ray emission of Ar is measured for 1.2 MeV Arq+(q=4, 6, 8, 9, 11, 12) ions impacting on V target and 3 MeV Ar11+ ions interacting with selected targets (Z2 = 23, 26, 27, 28, 29, 30). It is found that the measured Ar Kα and Kβ x-ray energies shift to the high energy side, and the relative intensity ratios of Kβ/Kα are enlarged than the atomic data, owing to the presence of out-shell multiple vacancies. The multiple ionization is almost independence of the projectile charge state, but is diminished with increasing target atomic number.

Highlights

The interaction of highly charged ions (HCI) with solid target has been intensively investigated in recent years, for the significance of basic researches such as, astrophysics, atomic physics and ion-atom collisions reactive dynamics under extra conditions, and for the requirement of practical applications in many fields, i.e., biomedicine, material science and new energy development technology[1,2,3,4,5]
According to the previous investigation[16], the K shell is mainly ionized by direct coulomb collision, and that can be well simulated by binary encounter approximation (BEA) the corrections of coulomb repulsion and ionic binding energy
Except for Arq+ ions having two M2 electrons, there is no 3 P electrons for other ions as Arq+ (q=6, 8, 9, 11, 12), which is directly related to the Kβ radiation

Summary

Introduction

The interaction of highly charged ions (HCI) with solid target has been intensively investigated in recent years, for the significance of basic researches such as, astrophysics, atomic physics and ion-atom collisions reactive dynamics under extra conditions, and for the requirement of practical applications in many fields, i.e., biomedicine, material science and new energy development technology[1,2,3,4,5]. In the lower energy region, the kinetic energy of HCI is too small to induce the direct ionization of inner-shell electrons, and the resulting interaction is mainly the neutralization of projectile in the vicinity of the surface by the charge exchange between the ion and target atom[22], and that can be well described by the classical over-barrier model (COBM)[23]. In addition to the inner-shell single ionization, under the dual effects of neutralization and ionization, the projectile may remain multiple-ionization state in the outer shells when the inner-shell x-ray emission occurs. This results in the blue shift of the corresponding x-ray energy and the change of the relative intensity ratio of the sub-shell x ray. We would like to present the further research, and the special attention will be devoted to the influence of projectile charge state and target atomic number on the multiple ionization

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