POLARIZED OPTICAL-ABSORPTION AND EMISSION-SPECTRA AND THE ELECTRONIC ENERGY-LEVEL STRUCTURE OF TB(DPA)(3)(3-) COMPLEXES IN B0.05(DPA)(3)]CENTER-DOT-NACLO4-CENTER-DOT-10H(2)O

Polarized optical absorption and emission measurements are used to loc ate and assign 60 crystal-field energy levels split out of the 4f(8) e lectronic configuration of Tb3+ in single crystals of Na-3[Yb0.95Tb0.0 5(dpa)(3)]. NaClO4 . 10H(2)O (where dpa drop dipicolinate dianion drop 2,6-pyridinedicarboxylate). In these crystals, each Tb3+ ion is coord inated to three dipicolinate (dpa) ligands, and the tris-terdentate Tb (dpa)(3)(3-) chelate structures have trigonal-dihedral (D-3) symmetry. The combined optical absorption and emission measurements provide acc ess to the energy-level structures of the 17 lowest-energy 4f(8)[SL]J multiplet manifolds of Tb3+, and all of these multiplet manifolds are represented among the 60 crystal-field levels that are characterized w ith respect to both location (energy) and symmetry properties. The ene rgy-level data obtained from experiment are analyzed in terms of a mod el Hamiltonian that includes consideration of both isotropic and nonis otropic 4f-electron/crystal-field interactions. A parametrized form of this Hamiltonian is used to perform parametric fits of calculated-to- experimental energy-level data, and the results obtained from these da ta fits show a root mean square (rms) deviation of 10 cm(-1) between c alculated and observed energies. The Hamiltonian parameters evaluated from the energy-level analyses provide information about both the anis otropies and the overall strength of the 4f-electron/crystal-field int eractions that contribute to the energy-level structure of Tb(dpa)(3)( 3-) complexes. In addition to energy-level data, the polarized emissio n measurements performed in this study yield information about the rel ative electric- and magnetic-dipole mechanistic contributions to emiss ion line intensities in the F-7(J)(J=0-6)<--D-5(3)(4) transition regio ns of Tb(dpa)(3)(3-), and this information is used to help rationalize the observed chiroptical luminescence properties of enantiomerically resolved Tb(dpa)(3)(3-) complexes in solution.