Role of Ion-Surface Interaction at the Entry Surface on the Energy Loss of Highly Charged Slow Ions in Solids

Tapan Nandi

doi:10.4236/ojm.2011.13009

Abstract

Evidence is obtained from the data of an earlier measurement that the effect of ion-surface interaction on the stopping power of highly charged slow ions is not at all tiny rather remarkably large, even it supersedes the bulk stopping power. The stopping power due to the surface interactions is directly proportional to the charge state of incident ions.

Highlights

Energy dissipation of charged particles moving through matter [1] has been of interest since the discovery of charged particles
Schenkel et al [8] experimentally observed that the charge state dependent energy loss of slow ions in solids was not explained with calculated values using the TRIM code [9]
It has recently been shown that the surface wakefield at the exit surface rather plays an important role on the ions [3]. Such a field is not possible to exist for highly charged slow ions as it originates from surface plasmons at the exit side due to passage of swift ions with velocity greater than the Fermi velocity

Summary

Introduction

Energy dissipation of charged particles moving through matter [1] has been of interest since the discovery of charged particles. Papaléo et al [11] reported direct evidence for a strong dependence of the surface modification as a function of charge state of the incident ions It implies that energy deposition near the surface varies with charge state. There are direct experimental evidences [8,12] showing that higher charge states of the slow incident ions have higher stopping power in solids This charge state dependence is explained in terms of charge pre-equilibrium effects. It has recently been shown that the surface wakefield at the exit surface rather plays an important role on the ions [3] Such a field is not possible to exist for highly charged slow ions as it originates from surface plasmons at the exit side due to passage of swift ions with velocity greater than the Fermi velocity. We show that some retarding force still exists due to ion-surface interaction that leads to the surface stopping power at the entry surface

Background

Results and Discussions

Conclusions