ELECTRON-ION COLLISIONAL IONIZATION CROSS-SECTIONS FOR THE H AND HE ISOELECTRONIC-SEQUENCES

In this work, we calculate the electron impact ionization cross sectio ns for H-like and He-like isoelectronic-sequence ions by means of a di storted-wave Born exchange approximation method including a relativist ic correction. A computer program has been developed and used to calcu late these cross sections. Systematic study of the dependence of the c ross sections on impact energies and nuclear charges is carried out. T he results of calculations are fitted by empirical formulas to meet th e requirements of applications. The fitted values are in good agreemen t with the calculated results. (C) 1995 Academic Press Inc.