ACCURATE CALCULATION OF TRANSITION-PROBABILITIES USING ORTHOGONAL OPERATORS

The accuracy of transition probabilities calculated from orthogonal op erators is increased by including valence correlations in the transiti on matrix. In this way, the interaction with infinitely many configura tions can be included perturbatively without the need to deal with hug e matrices. The effectiveness of the method is exemplified by a compar ison of the transition array 5d(9) --> 5d(8)6p in Hg IV, Tl V, Pb VI a nd Bi VII calculated with the strongly interacting 5d(8)6s taken into account both explicitly and using the above perturbative procedure.