Algebraic symmetry and determination of the “imaginary” crystal field parameters from optical spectra of fn-ions. Hexagonal and trigonal symmetry
1986; Elsevier BV; Volume: 102; Issue: 3 Linguagem: Inglês
10.1016/0301-0104(86)80014-3
ISSN1873-4421
Autores Tópico(s)Lanthanide and Transition Metal Complexes
ResumoAlgebraic symmetry of the characteristic equation of the crystal field hamiltonian ĤCF for hexagonal (C6, C3h, C6h) and trigonal (C3, S6) symmetry is considered. Explicit dependence of the coefficients ai of the characteristic equation on the CF parameters is derived by ALTRAN. Magnitudes, signs and/or relative signs of the CF parameters which can be determined from fitting the optical spectra of fn-ions at sites of the above symmetry are established. The algebraic results derived here can facilitate the fitting procedures for any hexagonal and trigonal symmetry. The relevant literature is extensively surveyed. The approach C (complete) to fitting the optical spectra, which yields ambiguous and unreliable results in general, has not been employed to hexagonal (C6, C3h, C6h) symmetry. Some misinterpretations on the approach R (reduced) and A (approximated), which merge for this symmetry, are clarified. Crystal field analysis has been carried out for trigonal (C3, S6) symmetry in but a few cases only. The survey has revealed one case of the inappropriate C used for Eu3+ in the trigonal (C3) Eu(DBM)3 · H2O system.
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