Rare Earth Ion-Host Crystal Interactions. 3. Three-Parameter Theory of Crystal Fields.
HARRY DIAMOND LABS ADELPHI MD
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A systematic approach in selecting solid-state materials that offer promise as new lasers with predetermined characteristics is of fundamental importance. Reliable predictions of the energy levels and transition probabilities of a laser active ion in a given host would greatly facilitate this goal. The three-parameter theory of crystal fields is used to derived crystal-field parameters for the first rare-earth series, lanthanides, in CaWO4. The parameters q and eta of the theory describe covalent effects in the host lattice q represents the effective oxygen charge, and eta represents the effective oxygen-tungsten distance. The third parameter tau represents the expansion of the radial 4f wavefunction from its Hartree-Fock value. Values of tau are found for the ions Nd3, Tb3, Dy3, Ho3, Er3, and Tm3, and are determined for the other rare earths by a linear fit. Energy levels and ground state g-values are calculated using the derived crystal-field parameters.
- Physical Chemistry