Symmetric and Asymmetric Collisions in Auger Electron Emission from Al, Mg, Si, and MgxAl1-X, Targets Induced by Low keV Ion Bombardment

Abstract

Auger electron spectra of Mg, Al and Si obtained by Ar+ bombardment on solid surfaces show some narrow line structures (∼1 eV wide) and an underlying broad feature which are assigned to atomic-like L23MM and bulk-like L23VV transitions respectively1. Hole in the inner L-shell is produced in collisions between projectile and target atoms (asymmetric or p-t collisions) or between two alike target atoms in the collisional cascade (symmetric or t-t collision). The adiabatic approximation is usually employed in calculating the evolution of the electronic states of the quasi-molecule formed transiently during the collision as a function of the internuclear distance. Starting from these adiabatic curves Barat and Lichten proposed a “diabatizing” mechanism allowing the otherwise avoided crossing whenever the degeneracy allows the overlap of two molecular orbitals (MO)2, thus one can attempt to follow the most probable path of one electron during a collisional event. For L-shell excitation occurring in the lighter partners in asymmetric collisions and in one or both atoms in symmetric collisions, Fano and Lichten proposed the electron promotion along the steeply rising, diabatic 4fσ MO3.KeywordsCollisional EventHigh Energy SideAuger Electron SpectrumAtomic PeakAuger Electron EmissionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.