NEAR-THRESHOLD BEHAVIOR OF GENERALIZED OSCILLATOR-STRENGTHS FOR 2P-IONIZATION

Near the ionisation threshold, the behaviour of the generalised oscill ator strength (GOS) is sensitive to the choice of the model atomic pot ential. In electron-impact ionisation, 'delayed maxima' of the GOS oft en occur near the ionisation threshold due to centrifugal barrier effe cts. 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 nonrelativisti c Hartree-Slater potential and the relativistic RCXI potential. Calcul ations have been done for electron-impact 2p ionisation of atomic oxyg en, neon, aluminium, argon, iron and zinc. The GOS results for 2p ioni sation of oxygen and aluminium are presented to illustrate the results .