W. Rybaromanowski et al., THE INFLUENCE OF NONRADIATIVE ENERGY-TRANSFER ON THE EXCITATION AND DECAY OF EXCITED-STATES OF ER3+ IN CS2NAERCL6, Journal of physics. Condensed matter, 6(8), 1994, pp. 1593-1602
Evidence for efficient non-radiative energy transfer between erbium io
ns in Cs2NaErCl6 is provided by excitation and luminescence spectra an
d luminescence lifetimes. In one of the cross relaxation schemes the e
xcitation of the 4F3/2 level is transferred almost exclusively to the
4F9/2 level in the 50-300 K temperature region. The process of cross r
elaxation which removes the excitation from the 4S3/2 level is switche
d thermally at about 100 K and attains high efficiency at room tempera
ture. Experimental results are interpreted using previously reported e
nergies of normal vibrations of ErCl(6)3- and the crystal-field levels
of Cs2NaErCl6. It has been noted that virtually all efficient energy
transfer schemes in Cs2NaLnCl6 reported thus far involve transitions b
etween multiplets of the ground terms of lanthanides. All these transi
tions obey the selection rules for magnetic dipole transitions.