Absorptions and emissions for the TmCl₆³- Ion in Cs₂NaTmCl₆

In this work we report both experimental and theoretical studies regarding the Cs₂NaTmCl₆ elpasolite-type system, for which we have an updated database from linear and nonlinear optics. Both the absorption and the emission spectra for this system are rather complicated and a generalized vibronic crystal field-closure-ligand polarization calculation model has been employed to rationalize the observed spectral intensities. The calculation has been carried out by neglecting the interaction among the internal and the external vibrations and theoretical calculations have been performed with reference to both the emissions ³H₄(Γ_i) → ³F₄(Γ_j) and the absorptions ³H₆(A₁) → ³F₄(Γ_i), ¹G₄(Γ_i), ³H₅(Γ_l) with Γ_k (k = i,j) = A₁,E,T₁,T₂ and Γ_l = E, ^aT₁, ^bT₁,T₂. The advantages and disadvantages of our model calculation are discussed in the text, and despite the simplicity of the model it is shown that it has got some utility and flexibility to gain understanding in these complex phenomena.