Existence states of deuterium irradiated into LiAlO2

The existence states of deuterium in LiAlO2 were analyzed by in situ IR absorption spectroscopy during irradiation with 3 keV D2+ at room temperature. Multiple IR absorption peaks that were related to O-D stretching vibrations were observed, mainly at 2650 cm−1 (O-Dα), 2600 cm−1 (O-Dβ), and 2500 cm−1 (O-Dγ). The O-Dα was assigned to the surface O-D. The O-Dβ and O-Dγ were interpreted as two distinct O-D states for three candidates: O-D of substitutional D+ for Li+; O-D of substitutional D+ for Al3+; and O-D of interstitial D+. O-Dβ was the dominant O-D state for deuterium irradiated into LiAlO2, and had higher stability than O-Dγ. Heating after ion irradiation led to the desorption of D2 and an increase in the intensity of O-Dβ, which implies that some of the deuterium irradiated into LiAlO2 exists in non-O-D states, such as D− captured by F centers.