ELECTRON-ION COLLISIONAL IONIZATION CROSS-SECTIONS FOR THE LI ISOELECTRONIC SEQUENCE

In this work, we calculate the electron impact ionization cross sectio ns for Li-like isoelectronic-sequence ions in the range 6 less than or equal to Z less than or equal to 29 by means of a distorted-wave Born exchange approximation method including a relativistic correction. Th e total cross sections include the contributions from direct ionizatio n and excitation autoionization. For excitation autoionization the bra nching ratio and the configuration interaction are considered. A packa ge of computer codes has been developed and used to calculate these cr oss sections. Systematic study of the dependence of the cross sections on impact energies and nuclear charges is carried out. The results of the calculations are fitted by empirical formulas to meet the require ments of applications. The fitted values are in good agreement with th e calculated results. (C) 1996 Academic Press, Inc.