Abstract
The crystal-field-split levels of divalent, trivalent, and tetravalent uranium ions have been studied at 20 °K in selected crystals having single charge-compensation sites. Complete calculations have been made for the free-ion energy levels of , with the pertinent constants determined as , , , , , and . Also calculated crystal-field-split levels of in symmetry are compared to experimental values, and the various "best fit" values of the crystal-field constants determined. ESR results on trigonal Ca: are correlated with predicted values derived from optical measurements. Experimental studies of the ion in calcium fluoride are related to the probable configuration, . Crystal-field splittings of the lower levels of Ca: are determined from measurements of absorption and fluorescence at 20°K. The calculated value of for , based on approximate coupling conditions for the lowest levels, is 1560 , and is compared with a similarly calculated value for of 1520 . Experimental crystal-field-split levels of tetragonal Ca: are shown to fit symmetry requirements, and various laser wavelengths of Ca: are related to the level system derived from absorption and fluorescence measurements. Temperature shifts of crystal-field-split levels of uranium ions are also reported.
- Received 1 June 1970
DOI:https://doi.org/10.1103/PhysRevB.2.2273
©1970 American Physical Society