Comparison of Theoretical and Experimental Level Values of the n = 2 Configurations in the Boron Isoelectronic Sequence

Abstract

The examination of the level values of the n = 2 configurations, which was recently carried through for ions iso-electronic with Li, Be, O and F, has now been extended to the configurations 2s22p, 2s2p2 and 2p3 of the boron sequence. In this study, expressions of the form A + B(Z - C)-1 + a(Z - s)x are derived for the difference between observed and theoretical values of selected level intervals, the theoretical values being based on the calculations of Cheng, Kim and Desclaux. By this procedure, accidental errors in the experimental data are smoothed out and missing data are interpolated or extrapolated beyond the range of observations. In the case of the two strongly interacting levels 2s2p2 2S1/2, 2P1/2, however, the theory fails to reproduce the effects of the "avoided crossing" well enough to provide a useful frame of reference, and a more primitive method of extrapolation had to be used. The results of the examination are summarized in a table of recommended values for the 14 excited levels of the n = 2 complex, covering the range from Z = 7 to Z = 36, and a corresponding table of recalculated wavelengths, including intersystem combinations. Some experimental data reported in the literature are found to need revision.