Electronic Spectra of Cs 2 NaYbF 6 and Crystal Field Analyses of YbX 6 3- (X = F, Cl, Br) (original) (raw)

Detailed analysis of the vibronic structure in the electronic absorption spectrum of Cs 2 NaYbF 6 at temperatures between 10 and 300 K enables the crystal field energy level diagram of Yb 3+ in this cubic host to be deduced. Ultraviolet and visible laser excitation of Cs 2 NaYbF 6 , Cs 2 NaY 0.9 Yb 0.1 F 6 , and Cs 2 NaHo 0.99 Yb 0.01 F 6 give spectral features mainly due to Yb 3+ being situated at a range of defect sites. The 4f 13 crystal field analyses of octahedral YbX 6 3-(X ) F, Cl, Br) systems show the expected trends in parameter values, but the energy level fits are poor. Inclusion of the interaction with the charge-transfer configuration 4f 14 np 5 provides an exact fitting of energy levels for YbX 6 3-, and a smooth variation of ff and fp crystal field parameters for Cs 2 NaLnCl 6 (Ln ) Er, Tm, Yb) is observed.