The band spectra of the alkaline earth halides. II.─BaF, MgF

Abstract

In a previous paper an analysis of the gross structure of the band spectra of the CaF and SrF molecules has been made. We shall here deal with the spectra of two molecules of precisely the same external character, but one of which is simpler and the other more complex in its internal structure. MgF has one shell of eight electrons less than CaF, the other molecule BaF has a shell of 18 electrons more than SrF. The barium fluoride bands can be produced in the flame or arc, and, using the latter source, George measured these from spectrograms taken on a 21-foot grating. For purposes of analysis and the resolution of several doubtful points it was found necessary to obtain new measurements, and Tables I and II present the data obtained from several first order plates of very good definition taken on a 21-foot Rowland grating.