M. Voda et al., FANO ANTIRESONANCES IN THE OPTICAL-ABSORPTION SPECTRA OF CR3-DOPED LA3GA5.5NB0.5O14 AND LA3GA5.5TA0.5O14 CRYSTALS(), Physical review. B, Condensed matter, 49(6), 1994, pp. 3755-3759
The polarized optical absorption spectra of Cr3+ ions have been system
atically investigated in two acentric crystals with Ca-gallogermanate
structure: La3Ga5.5Nb0.5O14 and La3Ga5.5Ta0.5O14. Crystal-field parame
ters have been determined for both Cr3+-doped crystals. Features obser
ved in the long-wavelength 4A2-->4T2 absorption band of Cr3+ have been
associated with Fano antiresonances, due to interaction between the 2
E and 2T1 sharp levels and the vibrationally broadened 4T2 quasicontin
uum. The line shapes have been analyzed in terms of the four-parameter
theory of Fano, so that the interaction has been evaluated for both c
rystals and compared with other d3 ion-doped systems.