Resolving hydrogen binding sites by pressure - A first-principles prediction for ZnO

The binding sites and vibrational frequencies omega of H in ZnO are studied by first-principles total-energy calculations. In the past, different experiments have observed different primary H vibrational modes, making the comparison with theory, and hence the identification of the most favorable H site, difficult. Here, we show that by applying a hydrostatic pressure, one should be able to make an unambiguous distinction, in particular, between the bond center sites and antibonding sites. This is because w should increase with pressure for the former but decrease for the latter with the magnitude of calculated slopes about 4 cm(-1)/GPa, which should be large enough to measure. (C) 2005 American Institute of Physics.