Abstracts 2001

Abstract of Publication No. 385

Oliver S. Wenger and Hans U. Güdel
Optical spectroscopy of CrCl63- doped Cs2NaScCl6: Broadband near-infrared luminescence and Jahn-Teller effect
J. Chem. Phys. 114, 5832-5841 (2001)      Full Text (PDF)      DOI-Link     

Abstract: Single crystals of 4.1% Cr3+ doped Cs2NaScCl6 were studied by variable temperature optical absorption and luminescence spectroscopy. The 4A2g 4T2g transition exhibits a great deal of fine structure both in absorption and emission spectra. The dynamic Te Jahn-Teller effect in the Cr3+ 4T2g excited state is analyzed on the basis of the Ham quenching in the 4T2g spinor splitting and the vibrational fine structure in the 7 K 4T2g 4A2g luminescence spectrum. The combined effect of the a1g and eg distortions leads to a net axial compression of the CrCl63- equilibrium geometry by 0.029 , and an equatorial expansion by 0.088 in the 4T2g excited state relative to the 4A2g ground state. These results are compared to those from other Cr3+ doped chloride and bromide elpasolites, and their different room temperature luminescence uantum yields are discussed on the basis of their different 4T2g excited state distortions. Temperature dependent luminescence and lifetime measurements show that in Cr3+:Cs2NaScCl6 at room temperature the luminescence quantum yield is about 0.7.

Last modified: 13.12.11 by Gabriela Frei