Doubly and Triply Differential Cross Sections for Single Ionization of He by Fast Au53+ Using a Multi-Body Quasiclassical Model

F Frémont

doi:10.3390/atoms8020019

Abstract

A multi-body multi-center quasiclassical model was used to determine doubly- and triply-differential cross sections following single ionization in 3.6 MeV/amu Au53+ + He collisions. The present model improved recent calculations, in which free electrons were added in the collision to reproduce, at least qualitatively, the experimental binary peak. In the present calculations, the electrons, that were assumed to originate from the collisions of Au53+ with surfaces before colliding with the He target, were now considered to be in the field of the projectile, with nearly the same velocity. The agreement between the calculations and the experiment was improved, for both the doubly- and the triply-differential cross sections and was better than previous calculations based on quantum mechanics.

Highlights

During the last two decades, considerable theoretical work has been performed to analyze single-ionization (SI) following 3.6 MeV Au53+ + He collisions, for which the strong interaction between the outgoing projectile, the residual ionized He+ target and the emitted target electron requires →sophisticated treatments
The discrepancies observed around q⊥ = 1 a.u. may have several reasons: (i) the CTMC calculations were not well adapted to reproduce the experimental cross sections when the electron projectiles were involved during a collision; (ii) it must be recalled that the initial distribution in space and in momentum of the convoy electrons may have influenced the results; (iii) the interaction between the convoy electrons, that was neglected in the present work, may have changed the q⊥
The triply differential cross sections (TDCS) measurements and calculations presented a substantial challenge, as they can show up significant discrepancies which can be hidden in less differential cross sections

Summary

Introduction

During the last two decades, considerable theoretical work has been performed to analyze single-ionization (SI) following 3.6 MeV Au53+ + He collisions, for which the strong interaction between the outgoing projectile, the residual ionized He+ target and the emitted target electron requires. 0, the distance r e between an electron and the projectile axis arbitrarily since no detailed information exists on this distance It was verified, for distances is at maximum a few the convoy were assumed to be ininathe cylinder of length varying from 20 to a.u.,that the shape of the electrons final distributions (presented section) ze and base radius At re. 8 a.u., i.e., after 60 cm collision distance, the distribution maximum was even at t of initial convoy electrons of 10,000 in order to obtain good statistics and assuming no interaction. Even at most of the convoy electrons were able to reach the target within the approximation of independent t = 10 a.u., i.e., after 60 cm collision distance, the distribution maximum was located between. It will be shown that the agreement between our calculations and the experiment was remarkably good

CTMC Method

X 53 X 2

Triply Differential Cross Sections

Conclusions