Fluorescence of trivalent dysprosium in hexagonal zinc sulphide at 77°K

Abstract

The low-temperature fluorescence of Dy 3+ in hexagonal ZnS is reported. Systems around 17,000 and 20,500 cm −1, due to return from the resonance level to the 6 H |13⧸2 and 6 H |15⧸2 levels of the ground multiplet have been studied in detail. The assignment 4 I |15⧸2 is made for the resonance level. The fluorescent lifetime of the 4 I |15⧸2 → 6 H |13⧸2 transition was found to be 8 × 10 −5 sec, which is considerably shorter than the calculated radiative mean life. This is discussed in terms of vibronic interaction with the crystal lattice.