OPTICAL SPECTROSCOPY OF A CHROMIUM-DOPED (CH3)(2)NH2AL(SO4)(2)CENTER-DOT-6H(2)O SINGLE-CRYSTAL IN THE FERROELECTRIC PHASE

The chromium doped (CH3)(2)NH2Al(SO4)(2) . 6H(2)O crystal was obtained from solution by a slow evaporation method at 303 K and investigated in the ferroelectric phase below 150 K using optical spectroscopy. It was found that the Cr3+ ions in the crystal are situated in a strong c rystal field in which the (2)E State is the lowest. A single narrow R line associated with the (2)E-(4)A(2) phosphorescence indicates an und istorted octahedral Cr3+ Site in the host lattice. The O-H bonds in th e first coordination sphere induce efficient nonradiative transitions from the (2)E emitting state and the Cr3+ emission is completely quenc hed at temperatures above 150 K.