Abstract of Publication No. 345
M. F. Hazenkamp, A. C.
Stueckl, E. Cavalli and H. U. Güdel and
Low temperature polarized single-crystal absorption and luminescence spectra of
Cr(V)-doped YVO4 and the powder luminescence spectrum of Cr(V)-doped
YPO4 are reported and discussed. A rich fine structure and strong
polarization effects are observed in the near-infrared. Due to a strong
interaction of the Cr(V) ion with two Y3+ ions in the second
coordination sphere of the Cr(V) ion, the electronic ground state is different
from the one expected on the basis of an angular overlap calculation in which
only the four oxygen ligands are taken into account. This effect of the
Y3+ ions on the ground state of Cr(V) is confirmed by a density
functional calculation and by literature EPR data.
CrO43- bending modes are responsible for the
fine structure in the d-d transition and the resulting distortion in the
emitting excited state.