Dynamic observation of the behavior of 3 keV irradiated into Li2O using IR absorption spectroscopy

In order to understand the influence of radiation defects on hydrogen isotope behavior in Li2O, an in situ IR absorption analysis was carried out during 3 keV D 2 + irradiation. Three IR absorption peaks were obtained from the stretching vibrations of O–Ds in different existence states: an O–D existing as a LiOD phase at 2710 cm−1, a surface O–D with several adjacent O–Ds at 2660 cm−1, and an O–D affected by a defect in the bulk at 2605 cm−1. At the outset of the irradiation, only the surface O–D appeared. As the ion fluence increased, the O–D affected by a defect started to form in the bulk, and the LiOD phase followed it. The defect related with the O–D at 2605 cm−1 was regarded as a Li vacancy. It was indicated that the hydrogen isotopes were stabilized in Li2O through an interaction with the Li vacancy (LiO−–D+: 2605 cm−1) or mutual aggregation (LiOD phase: 2710 cm−1).