Z. Gajek et al., OPTICAL-ABSORPTION SPECTRA OF THE URANIUM-(4+) ION IN THE THORIUM GERMANATE MATRIX, Journal of physics. Condensed matter, 9(2), 1997, pp. 557-567
Visible and infrared absorption measurements on the U4+ ion in tetrago
nal zircon-type matrix beta-ThGeO4 are reported and analysed in terms
of the standard parametrization scheme. The observed 17 main peaks and
a number of less intense lines have been assigned and fitted to most
of the 32 allowed electric dipole transitions with the root mean squar
e error equal to 65 cm(-1). The free-ion parameters obtained for the m
odel Hamiltonian, zeta(5f) = 1809 cm(-1), F-2 = 43065 cm(-1), F-4 = 38
977 cm(-1) and F-6 = 24391 cm(-1), as well as the corresponding crysta
l-field parameters, B-0(2) = -1790 cm(-1), B-0(4) = 1200 cm(-1), B-4(4
) = 3260 cm(-1), B-0(6) = -3170 cm(-1) and B-4(6) = 990 cm(-1), agree
fairly well with the initial theoretical estimations. The results are
discussed in relation to the previous spectroscopic study on the schee
lite-type matrix UGeO4.