title: Theoretical study of the crystal-field energy levels and two-photon absorption intensities of Tb3+ in cubic host lattices.
abstract: Published two photon excitation (TPE) intensities for the cubic elpasolite systems Cs(2)NaTbX(6) (X = Cl, F) have been simulated by a calculation of two photon absorption (TPA) intensities which takes into account electric dipole transitions involving the detailed crystal-field structure of 4f(7)5d intermediate states, as well as the interactions of the 4f(7) core with the d-electron. The intensity calculation employed parameters from an energy level calculation which not only presented an accurate fit, but also yielded parameters consistent with those from other lanthanide ions. The calculated intensities were used to confirm or adjust the previous assignments of energy levels, resulting in some minor revisions. Generally, the TPA intensity simulations were in better agreement with experimental data for the fluoride, rather than the chloride, system and possible reasons for this are given.
authors.affiliation: College of Physics and Mathematics, Chongqing University of Post and Telecommunications, Chongqing, P.R. China. duanck@cqupt.edu.cn
authors.forename: Chang-Kui
authors.initials: CK
authors.lastname: Duan
authors.forename: Peter A
authors.initials: PA
authors.lastname: Tanner