Trapping and emission centres in X-irradiated zircon. II. Contribution of the SiO44− groups

Abstract

The 365 nm emission band observed at 100, 165, 205, 260, and 325 K in the thermoluminescence of undoped zircons, synthesized with the hydrothermal method, and which are X-irradiated at 77 K, is attributed to the SiO lattice groups. It is established that a paramagnetic trap centre is associated to most TL peaks. These traps are fairly well described by the Curie model: an electron is trapped in the field of two positive charges, one substituted to silicon, the other to a neighbouring oxygen. La bande d'emission situee autour de 365 nm et apparaissant a 100, 165, 205, 260 et 325 K dans la thermoluminescence de zircons non dopes, synthetises par la methode hydrothermale, et ayant subi une irradiation X a 77 K, est attribuee aux groupements du reseau SiO. Il est montre qu'a un pic de thermoluminescence est en general associe un centre de piegeage paramagnetique, et que ces derniers sont assez bien representes par le modele de Curie: un electron est piege dans le champ de deux charges positives, l'une substituee a un silicium, l'autre a un oxygene voisin.