摘要
Ⅰ. INTRODUCTIONApplying the approximate model potential theory to multi-electron atoms or ions suggested in Zheng’s papers, the authors of the present note have derived a general expression for the calculation of matrix elements of the operator r^k with arbitrary power order k, which can be applied in calculating various transition oscillator strengths. In order to study the multiplet structure at any excited state, we need to calculate the spin-orbit coupling ener-
