Production and reaction kinetics of radiation-induced defects in α-alumina and sapphire under ion beam irradiation

Reaction kinetics of radiation-induced defects in vitreous silica under ion beam irradiation

“…In the present study, similarly to the case of alumina [3], the irradiation time dependence of the luminescence intensity was measured of vitreous silica, and it was found that a considerable part of the luminescence comes from ODCs accumulated by irradiation. The observations were analyzed in order to improve our knowledge on the production mechanisms and kinetics of the radiation-induced defects.…”

“…This fact suggests that a considerable part of the luminescence comes from the defects accumulated by irradiation and that the intensities at these bands may reflect the amounts of the defects. Thus, similarly to the case of alumina [3], this in-situ luminescence measurement technique can be applied to monitor radiation-induced defects under irradiation; different irradiation time dependences which are observed for different specimens in Fig. 3 and for different temperatures in Fig.…”

“…If the luminescence is only observed on producing the defect, and if there is no change in the efficiency or mechanism, the luminescence would be constant. However, this may not be the case for some emissions including the 460 nm emission of ODCs, the luminescence is more likely to be related to the total number of stable defects produced (or their counterpart, interstitials), as reported for alumina [3]. It is thus needed to check the validity of the earlier assumptions.…”

Oxygen interstitial structures in close-packed metal oxides

“…The triplet path is a monotonically increasing function, confirming the triplet as a minimum, and an extended plateau region in the peroxy stretching region, approximately [ The overall height of the barrier is only 0.03 eV, which may be an artifact of the GGA level of theory used and more accurate electronic structure techniques will be required to ascertain the barrier height. With regard to oxygen transport, which is of high current interest [2][3][4], these calculations allow us to draw only preliminary conclusions. Important alternative mechanisms should be investigated elsewhere; however, our preliminary results suggest that migration of the peroxide species is a feasible process with an activation energy of 0.73 eV across the hexagonal (1 0 0) plane.…”

“…Here we focus on a-alumina, an important dielectric material that is used in a variety of technological and catalytic applications and has been the focus of considerable experimental investigation, with particular emphasis on its mechanical and atomic transport properties [2][3][4][5]. Furthermore, many theoretical studies of defects in Al 2 O 3 have been reported based on classical interatomic potential [6][7][8][9][10], semi-empirical [11][12][13], Hartree-Fock [14], density functional [15,16], and most recently hybrid density functional methods [17,18].…”