The optical absorption spectra of KC1 crystals containing TI+ ions have been investigated. After X-ray irradiation at 300 K two absorption bands are observed at 228 and 280 nm at 77 K whichdo not arise from the same centres. A correlation among the 228 nm. 280 nm. and F bands is found during the optical or thermal excitation of the X-rayed crystals. The 228 nm band is assigned to a trapped-hole centre, namely V2 centre closely associated with TIt. while the 280 nrn hand is assigned to a trapped-electron centre, TI-. On a etudik le spectre d'absorption optique de crist;~ux de KC1 contenant des ions TI+. Apres irradiation aux rayons X I 1 300 K, on a observC i 228 et 280 nm h 77 K , deux bandes d'absorption qui ne proviennent pas des memes centres. On trouve une corl.Clation entre les bandes i 228 nm, la bande 280 nrn et la bande F durant I'excitation optique ou therrnique des cristnux il-radies ;tux rayons X. La bande h 228 nm est attribuCe B un centre i trou piCge. c'est-i-dire un centre V2 Ctroitement associke 1 TI+. alors que la bande : I 280 nm est attribuee h un centre ,;I electron piege, TI-. Can. J . Phys.. 57. 1510(1979) [Tnduit par le journal] Can. J. Phys. Downloaded from www.nrcresearchpress.com by University of P.E.I. on 11/18/14 For personal use only.