Energy Levels of the Ground Term of Triply Ionized Terbium in Calcium Tungstate

摘要

An investigation of the absorption spectrum of Tb(+++) in CaWO4 over the infrared region was made to determine crystal field parameters. These parameters may aid in explaining the effect of crystalline fields upon the lasing properties of rare-earth ions when placed in host crystals of scheelite structure. Transitions were observed from our energy levels of the 7F6 ground state to energy levels of the 7F0, 7F1, 7F2, and 7F3 multiplets, where the crystal temperatures were between approx. 4.2 and approx. 77K. Effective crystal field parameters, B lm = A lm (rl), were determined by a least-squares-fit of calculated to measured energy levels. Russell-Saunders wave functions were used, and j-mixing was neglected in calculating the theoretical energy levels. The effective crystal field parameters were found to be: B20 = 386 plus or minus 64/cm, B40 = -534 plus or minus 55/cm, B60 = -183 plus or minus 86/cm, B44 = 302 plus or minus 217/cm, and B64 = 875 plus or minus 60/cm. (Author)