Role of the 4f55d band in the radiationless 5D1→5D0 coupling in BaCl2:Sm2+ and BaBr2:Sm2+

Autor:	F. K. Fong, H. V. Lauer
Rok vydání:	1976
Předmět:	Coupling education.field_of_study Phonon Chemistry Population Relaxation (NMR) General Physics and Astronomy Relaxation theory Fluorescence Physical and Theoretical Chemistry Atomic physics education Adiabatic process Excitation
Zdroj:	The Journal of Chemical Physics. 65:3108-3117
ISSN:	1089-7690 0021-9606
DOI:	10.1063/1.433524
Popis:	In this paper, the adiabatic relaxation theory is applied to investigate the origin of rare‐earth fluorescence quenching involving multiphonon transitions. The energy level schemes for BaCl2:Sm2+ and BaBr2:Sm2+ have been obtained from the observed fluorescence spectra. The phonon cutoff frequencies, 210 and 140 cm−1 for BaCl2 and BaBr2, respectively, have been determined from vibronic sidebands. From the observed temperature dependence of the fluorescence intensities and lifetimes, it is shown that the 5D1 and 5D0 levels are thermally quenched through radiationless excitation to the 4f55d band and that the population of the 5D0 level from 5D1 involves the 4f55d band as an intermediary. This indirect f (→d) →f relaxation mechanism appears to have resulted from the proximity and relatively large displacement between the adiabatical surfaces of the low‐lying 4f55d and the 5D1 states of Sm2+ in BaCl2 and BaBr2.
Databáze:	OpenAIRE
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