The optical UV-vis-NIR as well as high-resolution FT-IR absorption spectra
of the tetragonal HoOCl were measured at selected temperatures between 9 an
d 300 K. The luminescence spectra of LaOCl: Ho3+ and GdOCl : Ho3+ were obta
ined at 77 K and room temperature. The energy level scheme of Ho3+ (4f(10)
electron configuration) in HoOCl was simulated with a Hamiltonian of 20 par
ameters. The procedure consisted of a simultaneous diagonalization of the f
ree ion and crystal field (c.f.) interactions with a untruncated set of wav
e functions for the CS, point symmetry of the Ho3+ site in REOCl. Good agre
ement was achieved (rms deviation: 20 cm(-1)) between 181 experimental and
calculated energy level values. The results were found consistent with thos
e for Pr3+,Nd3+, Sm3+, Eu3+, Tb3+, Dy3+, Er3+, and Tm3+ in respective REOCl
matrices. (C) 2000 Elsevier Science B.V. All rights reserved.