The ¹I₆ state of Pr³⁺ in LaCl₃ at 77° K

Abstract

A single crystal of 5% Pr³⁺ in LaCl₃ was grown by Stockbarger's method and its absorption spectrum at 77° K. recorded in the region 4200-5400 Å on a grating spectrograph having a dispersion of 5 Å/mm. in the first order. Polarization of the absorption lines has also been obtained. In the group of lines arising from ¹I₆←³H₄ transition, six more lines in addition to the four previously known have been observed. Satisfactory analysis of all these ten lines is given. One additional Stark level in ¹I₆ is established at 21407 cm.^-1 with μ=1. For a few lines the polarization results obtained here do not agree with those of previous workers but fit in satisfactorily in the analysis.