FINE STRUCTURE IN ABSORPTION SPECTRUM OF ALPHA-MNS

Fine structures in absorption spectra of ±-MnS single crystals are investigated at low temperatures. The sharp and temperature-independent band C: 6A1 ⟶[ 4A1, 4E ] has five components, which can be explained in terms of covalency, descent of the crystal field symmetry and phonon-assisted transitions. In the visible and near-ultraviolet regions, five absorption bands are observed. The calculated band positions are fit for the observed bands at 4.2°K with the covalency parameter ɛ =0.17, the Racah parameters B =808 cm-1, C =3751 cm-1 and the crystal field strength Dq =1025 cm-1. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.