DYNAMICS OF SOME RADIATIONLESS TRANSITIONS IN EUROPIUM CHELATES
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Date
1973
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Publisher
Ohio State University
Abstract
Time-resolved, wavelength-resolved studies of the emission from the $^{5}D_{1}$ and $^{5}D_{0}$ electronic states of Eu (III) in several 6- and 8-coordinate chelates in low temperature glasses have been made. On laser excitation into ligand singlet bands, the $^{5}D_{1}$ state is populated very rapidly $(\tau < 10$ ns) and decays with a lifetime $\tau = 1.8\mu s$. The $^{5}D_{0}$ state is populated by at least two processes: one is very rapid $(\tau < 10$ ns), the other is much slower $(\tau=1.8\mu s)$ and is clearly visible as an initial rise in emission intensity. The rate of population of $^{5}D_{0}$ by the slow process corresponds to the $^{5}D_{1}$ depopulation rate. This is the first time-resolved demonstration of a slow radiationless transition rate from an upper excited state in a rare earth metal. We have investigated the dependence on temperature and on ligand triplet energy level in different complexes.
Description
Author Institution: Department of Chemistry, University of Illinois