Analysis of the Spectrum of Se II

An analysis of the spectrum of Se II is given with additions and corrections to that by Krishnamurty and Rao. The spectrum of selenium in this investigation was excited in a hollow cathode discharge with a helium atmosphere. Wave-length measurements were made in the region 500 to 2600A with a 1.5-meter grating vacuum spectrograph. New terms belonging to the $4s^{2}4p^{2}5p$ configuration have been found and identified. Several other terms, probably associated with the $4s^{2}4p^{2}4d$ and $4s^{2}4p^{2}5d$ configurations, have been found and $J$ values assigned, but it has been found impossible at present to assign $L$ and $S$ values to them. Tables of all term values and line classifications known at present are listed.