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The absorption spectra of Sm2+ doped in MFX (M=Sr, Ba; X=Cl, Br) crystals were studied within the range of 20,000β35,000 cmβ1 as a function of temperature and host. The absorption bands observed were described with a simple model developed by Wood and Kaiser using group theory. The temperature and host dependence on the 7F0β5D3 Fano resonance lines were investigated. BaFCl:Sm2+ system showed a βnormalβ 7F0β5D3 transition at 4 K in spite of similar crystal structure and absorption profile with other MFX hosts. New Fano resonances were observed in the absorption spectra at higher energies (23,000β25,000 cmβ1) for all MFX:Sm2+ systems at 4 K which persist up to room temperature. Preliminary energy level calculation showed that these resonance lines involve the interaction between higher excited 5LJ states of 4 f6configuration and 4 f55d1 configuration. |