Ultraviolet (UV) and vacuum ultraviolet (VUV) luminescent prtoperties of En^3 and Tb^3+ in LnBaB~9O~16(Lu=La,Gd,Y,Lu have been systematically studied. LnBaB~9O~16 crystallizes in trigonal system. The emission spectra of Eu^3+ in these matrices show that the local symmetry of rare earth atoms depends on the ionic radii of the Eu^3+ ions. Rare earths from La and Gd are located in noncentrodymmetric sites, and those from Y to Lu occupy centrosymmetric sites. The predominant emission of Eu^3+ is^5D~0 →^7F~2 in LnBaB~9O~16 and GdBaB~9O~16 and^5D~0 -→^7F~1 in YBaB~9O~16 and LnBaB~9O~16. The emission spectra of Tb^3+ also exhibit different behavior, which contain^5D~4→^7F0 and ^5D~4→ ^7F~J(J=3～6) teansitions in LnBaB~9O~16 and GdBaB~9O~16 and only ^5D~4→^7F~J(J=3～6) transitions in LnBaB~9O~16 and GdBaB ~9O~16 and only ^5D~4→^7F~J(J=3～6) transtion in YBaB~9O~16 and LnBaB~9O~16. Tje emission intensity of Tb^3+ is much weaker in LnBaB~9O~16 and GdBaB~9O~16 than in YBaB~9O~16 and LnBa B~9O~16and reverse behavior was observed in Eu^3+ doped system. All these materials show weak sbsorption in VUV range.

Key words: EUROPIUM, TERBIUM, BORATES