High pressure action on the SA and Mn emission in the cubic, faulted and hexagonal ZnS crystals

The pressure coefficient dE/dP appears to be sensitive to the ZnS lattice symmetry for the SA donor-acceptor pair, but not for the Mn2+ centres emission. The HP variation of the relative intensities for the SA and Mn emissions suggests a resonant transfer between these centres. The classical Dexter's formula for Pdd does not explain the results for the cubic crystal, whereas the preferential transfer from the SA centers to the 4E(4G) level in Mn2+ follows all reported observations.