Near Resonance Interactions between Stark Components of the 6H5/2 and 4G5/2 States of Sm3+ in POCl3:SnCl4
Light excitation of Sm3+ ions in POCl3.:SnCl4 leads to fluorescence emission arising exclusively from the lowest excited state of Sm3+, namely the 4G5/2-state. The fluorescence lifetime of the 4G5/2-state of Sm3+ in POCl3:SnCl4 is fairly long (1), approaching 3.3 msec at very low [Sm3+] in contrast to the relatively short lifetimes of Sm3+ (4G5/2) observed in such solvents as CH3OH, C2H5OH, C3H7OH and H2O. Values of τfl equal to 10.5, 10.0, 9.0 and < 3.0 μsec have been reported for Sm3+ in these latter solvents (2). The fluorescence lifetime and quantum yield of the 4G5/2- state of [Sm3+] in POCl3:ZrCl4 and POCl3:TiCl4 decrease with increasing [Sm3+] due to the self-quenching (1,3) of the 4G5/2 by the 6H5/2-state of Sm3+. In addition, the fluorescence is quenched by the solvent, ksol, whose maximum value is 320 sec−1 (4). The temperature dependence of the self-quenching process of the 4G5/2- state of Sm3+ will be discussed in this article. Experimental details regarding this study were given elsewhere (2,3,5).
KeywordsManifold Expense Fluores TiCl POCl3
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