Near-threshold Behaviour of Generalised Oscillator Strengths for 2p Ionisation

Abstract

Near the ionisation threshold, the behaviour of the generalised oscillator strength (GOS) is sensitive to the choice of the model atomic potential. In electron-impact ionisation, 'delayed maxima' of the GOS often occur near the ionisation threshold due to centrifugal barrier effects. In the present work, the sensitivity of this important effect of the centrifugal barrier to the model atomic potential has been studied using two local density atomic potentials, namely, the nonrelativistic Hartree-Slater potential and the relativistic RCB potential. Calculations have been done for electron-impact 2p ionisation of atomic oxygen, neon, aluminium, argon, iron and zinc. The GOS results for 2p ionisation of oxygen and aluminium are presented to illustrate the results.