STARK ENERGY LEVELS OF 5 D 4 , 7 F J ( J =0—6)OF Tb 3+ IONS IN TbP 5 O 14

Abstract

In the present paper, the polarized fluorescence spectra and the infrared absorption spectra of single crystals of terbium pentaphosphate, TbP5O14 , were measured at 77 K. Most of the observed transitions were identified and the energy level structure of the ~7F multiplet was also defined. The result of structure analysis indicates that the coordination of the cation to oxygen atoms is eightfold with the geometry of a slightly distorted square antiprism. In other words, the local symmetry of the Tb3+ in TbP5O14 belongs to C 4 v . The crystal field calculations were performed for such symmetry and gave a respectable fit for the observed Stark splitting of the 7FJ( J = 0--6) multiplet. The comparison between the experimental and the calculated energy levels shows that the rms deviation and the maximum deviation are 8cm-1 and 17cm-2, respectively.