The hyperfine structure of some lines in the arc and first spectrum of indium

Abstract

This investigation of lines in the arc and first spark spectrum of indium was undertaken with the purpose of evaluating, if possible, the nuclear moment of the indium atom. As far back as 1922 Uhler and Tanch had studied the structure of some lines in the ultra-violet, but their results did not seem to admit of an interpretation based on a quantum number “I.” In the present investigation the spectra were excited in stages as in the earlier work with thallium j by altering the pressure of the vapour in the discharge tube. The analysing apparatus was also the same as that previously employed, namely, a 45 plate high power echelon spectrograph. Ilford “Soft Gradation” plates were used with exposures of 15 minutes to half-an-hour.