The series spectra of two-valence-electron atoms of phosphorus (PIV), sulphur (SV), and chlorine (ClVI)

Series spectra of two-valence-electron atoms of P, S, and Cl.—In a previous Paper(1), the regular and irregular x-ray doublet laws were used to predict the spectra of stripped atoms, that is, atoms having only one valence electron. The method has now been applied to the spectra of two-electron atoms, since, although these spectra consist of triplets or singlets instead of doublets, the same laws apply to them. In this way 23 lines of PIV have been identified, 17 lines of SV and 6 lines of ClVI. With the help of the Ritz equation, 12 term values of PIV and 8 of SV were also determined. In a table are collected all known term values for two-electron atoms of Mg, Al, Si, P and S. Physical significance of the x-ray irregular doublet law.—Spectral lines which give parallel curves on a Moseley diagram sqrt[ν/R] plotted as a function of atomic number) and which therefore follow this law, are produced by jumps between orbits of the same total quantum number but with different screening constants