The Spectrum of Gallium II And The (4s4p2) Configuration in Gallium I and Indium I

Abstract

The spectrum of gallium has been excited in a hollow cathode discharge in helium and photographed in the region from $\ensuremath{\lambda}10,000\ensuremath{-}\ensuremath{\lambda}200$. about 90 lines so excited have been classified in singlet and triplet series of Ga II. Peculiarities in the run of intensities in successive members of series have been found due to the excitation by helium which is sufficient to excite only terms greater than 12,000 $\ensuremath{\nu}$-units in this spectrum. Absolute term values are calculated and the lowest term is $(4{s}^{2})^{1}S=165458$ corresponding to an ionization potential for Ga II of 20.43 volts. Tables of classified lines and of term values are given. The lines arising from combinations of $(4{p}^{2})^{4}P$ and $(4{p}^{2})^{2}S$ with $(4s4p)^{2}P$ of Ga I have been identified and values of these terms are given. Preliminary work on the excitation of the indium spectrum in helium has enabled the location of $(4{p}^{2})^{4}P$ in In I and its term values and combinations with $(4s4p)^{2}P$ are given.