Abstract
We present an easy to use expression for cross sections of electron-impact-induced excitation transitions with in multiply charged ions of lithium isoelectronic sequence. This expression is based on our computations by convergent close-coupling (CCC) and Coulomb-Born with exchange and normalization (CBE) methods. We show scaling of the CCC and CBE cross sections with atomic number and use this scaling for presentation of the cross-section data. For the scaling is accurate to better than at any energy except in the vicinity of resonances. Contributions from indirect excitation channels do not scale with however, for calculation of excitation rates it is enough to average locally these contributions over energy and to take them into account in a frame of a general scaling-based expression for the cross sections. For excitation rates, total inaccuracy caused by all simplifications in the cross-section presentation is likely to be less than even for most risky cases. This assessment is based on comparison of excitation rates, computed using our scaling-based expression for the cross sections, with the excitation rates, computed using high-resolution (CCC and matrix) cross sections and experimental data.
- Received 23 April 1997
DOI:https://doi.org/10.1103/PhysRevA.56.3726
©1997 American Physical Society