Spectroscopic properties of alexandrite crystals II
1987; Elsevier BV; Volume: 37; Issue: 1 Linguagem: Inglês
10.1016/0022-2313(87)90179-7
ISSN1872-7883
AutoresA. Suchocki, Guy D. Gilliland, Richard C. Powell, John M. Bowen, J. C. Walling,
Tópico(s)Luminescence Properties of Advanced Materials
ResumoSeveral aspects of the optical spectroscopic properties of alexandrite crystals not previously investigated are reported here. For Cr3+ ions occupying the Al3+ lattice sites with mirror symmetry in BeAl2O4, the positions of the zero-phonon lines for absorption transitions to the 2T1g and 4T2g levels are identified, and vibronic transition peaks in the fluorescence spectrum are compared to transitions appearing in the Raman spectrum and Stokes excitation spectrum. In addition, the effects of radiation trapping are shown to lengthen the fluorescence lifetime of the 2Eg - 4A2g transition for ions in these sites at low temperatures. For Cr3+ ions occupying the Al3+ lattice with inversion symmetry, the ground state splitting of the 2Eg - 4A2g transition is reported and the decrease of the fluorescence lifetime with temperature is shown to be due to the increase in vibronic emission probability as well as increased probability of direct radiationless decay.
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