IV. Series and other regularities in the spectrum of manganese

Abstract

The discovery of the laws which govern the distribution of lines in spectra is of great importance in relation to the problem of the structure of the atom. Up to the present time nearly all the work on the regularity in the arrangement of spectral lines has dealt with spectra which have a relatively small number of lines. Important laws have been found which include most of the lines in these spectra, but in nearly all cases there remain some prominent lines whose relation to the regular series is not yet clear. It seemed possible that the careful study of a spectrum rich in lines would lead to the discovery of new or more general laws than those which have been found for elements comparatively poor in lines, and so enable us to classify many other spectra, and at the same time to interpret the lines which at present remain unclassified in those spectra with fewer lines. It was with this object that the present work was undertaken. The spectrum of manganese was chosen, because there were already some indications of series in this spectrum, analogous to those found in other elements, and it would naturally seem to make a good starting point.