On the variation of Stark line shifts within a given spectrum in the case of irregular energy level structure

The knowledge on regularities and systematic trends for Stark line shifts w ithin a given spectrum as e.g. similarities among Stark line shifts within a multiplet, supermultiplet or transitions array and systematic trends with in a spectral series, is useful for the interpolation of new data and the c ritical evaluation of experimental data. In this paper exceptions to the es tablished regularities have been analyzed on the basis of critically select ed experimental data as well as of results of semi-classical calculations. It has been demonstrated that the principal reason for the irregularities d iscussed is irregularities of energy level structure. An additional reason is the influence of the intercombination and forbidden perturbing transitio ns.