Influence of ligand spin-orbit coupling to the sign of the zero-field splitting and pressure-induced spectral shift for ZnS:Mn2+ (bulk/nanocrystal)

Serious difficulties exist in explaining the zero-field splitting (ZFS) of 3d(5+) ions in crystal, with the current crystal-field theory. The calculated cubic ZFS a-value of 5 ion is positive identically. However, K.A. Muller and W. Low found experimentally that a is negative for some ZnS:Mn2+ crystals. In this work, an unified explanation is developed for the ZFS, optical spectra and pressure-induced spectral shift for the ZnS:Mn2+ (bulk/nanocrystal) by considering the influence of the spin-orbit coupling to the ZFS and spectral bands. The excellent agreement between calculation and experiments shows that the above-mentioned difficulties can be removed based on the calculation model proposed by authors. Calculation result shows that there are two kinds of stable electron states with (lambda(pi), lambda(sigma), lambda(s)) = (0.2713448, -0.1619936, -0.08) and (0.2713448,0.346885, -0.220), respectively, where (lambda(pi), lambda(sigma), lambda(s)) denote the mixing coefficients of Mn2+ - 4S(2-) anti-bonding in ZnS:Mn2+. (C) 2004 Elsevier B.V. All rights reserved.