Resonant-scattering (autoionisation) contributions to excitation rates in O4+and similar ions

Publisher Website
Google Scholar
Abstract
Electron-impact excitation may occur either directly, or by a resonant process involving a doubly excited autoionising compound state. The contribution of the resonances is computed here by a perturbation method involving the principle of detailed balance and the calculation of autoionisation and radiative-decay transition probabilities. In ions of the Be I isoelectronic sequence, resonances are found to be of negligible importance for the strong 2s2 1S-2s2p 1P degrees excitation, but to provide 25 to 50% of the total excitation rate for the weak 1S-3P degrees excitation. For atoms more than 3 or 4 times ionised, this method-combined with distorted-wave calculation of the direct excitation process-should, in most cases, give total rates comparable in accuracy to detailed close-coupling calculations, and would appear to be particularly useful when departures from pure LS coupling are great or when radiative decay of the compound state is important.

This publication has 10 references indexed in Scilit: