Relativistic Effects in Atomic Fine Structure

Abstract

Operators are obtained which can be evaluated with respect to nonrelativistic wavefunctions to produce the same result as obtained by evaluating the Breit equation with respect to relativistic wavefunctions. This greatly simplifies calculations involving the Breit equation by allowing the calculations to be made within the more familiar framework of nonrelativistic theory. The operators are classified according to their angular dependence; a comparison with the angular dependence of each fine‐structure operator leads to the relativistic equivalents of the fine‐structure interactions. The operators are expanded in a power series in (v/c)², and the lowest nonvanishing terms are shown to be the fine‐structure interactions.