Analysis of the First Short Period and Its Isoelectronic Sequences

Abstract

The configurations $2p^n$, $2s2p^{n-1\mathrm{}}$, and $2s^{2}2p^{n-2\mathrm{}}$ are analyzed for all observed spectra of the respective isoelectronic sequences. The semiempirical Slater method is amended to include the polarization correction and, wherever possible, configuration interaction. The polarization parameter $\Lambda$ is found to be approximately linear in the degree of ionization, $q$. The Slater parameters characteristic of the term separations of $2s^{m}2p^n$ and of configuration interaction are found to be linear functions of $m$, $n$, and $q$, partly corresponding to the Bacher-Goudsmit theory in second approximation. A comparison with self-consistent field calculations is made. Other consequences of the analysis are discussed.