Infrared spectra and VUV excitation properties of BaLnB9O16:Re (Ln=La, Gd; Re=Eu, Tb)

The infrared spectra of BaLnB9O16:Re, along with the VUV excitation spectra, have been measured. The spectra were tentatively interpreted in terms of the data on absorptions of the borate groups and band structure. It was observed that there are absorption due to BO3 and BO4 groups, indicating that there are BO3 and BO4 groups in BaLnB9O16. It is found that absorption of the borate groups is located in the range from 120 to 170 nm. This result reveals that there is an energy transfer from host to the rare earth ions. It also observed that the energy of charge transfer band, the host absorption, the total crystal field splitting of d-levels of Tb3+ increase with the decrease in the Ln3+ radius.