Studies of OH− and OD− Ions in Magnesium Oxide. II. The Structure of the VOD Center

This paper reports EPR, ENDOR, and infrared absorption measurements on the V_OD center in MgO. The magnetic properties are well fitted to a spin Hamiltonian which includes terms due to electronic Zeeman, nuclear Zeeman, and hyperfine and nuclear quadrupole interactions. The magnitude of the unpaired electron spin density at the deuterium nucleus is similar to that for the hydrogen nucleus in the V_OH center. Infrared absorption due to the fundamental stretching vibration of the $\mathrm{O}–{\mathrm{D}}^{-}$ bond in the V_OD center occurs at 2464.5 cm⁻¹. The oscillator strength of this vibrational transition is small, being of order 10⁻². The analogous stretching frequency of the OH⁻ bond in the V_OH center in CaO is observed at 3447 cm⁻¹.