Defects in bulk zinc oxide were investigated by performing embedded cluster calculations within the density functional theory using the PBE functional. Equilibrium structures and vibrational spectra were obtained for interstitial hydrogen species and for hydrogen complexes at zinc vacancies and at substitutional atoms such as copper, beryllium, manganese and calcium in zinc positions. All of these defects differed in their vibrational frequencies, which could be attributed to existing experimental data. The agreement surpassed the results of earlier calculations within the local (spin) density approximation. This led to a better understanding of these bulk defects and helped to answer some open questions: for instance, the attribution of a signal observed in infra-red spectra at 3326/cm. The computed vibrational spectra could serve as a benchmark and assist in the interpretation of future experimental results.Investigation of Interstitial Hydrogen and Related Defects in ZnO. Kossmann, J., Hättig, C.: Physical Chemistry Chemical Physics, 2012, 14[47], 16392-9