Abstract
The influence of hydrogen diffusion on the Mossbauer spectra of 57Fe in NbH0.78 has been studied. The quasielastic Mossbauer line arising from the hydrogen-induced displacements of the probe atoms was observed directly. The temperature dependence of the hydrogen jump rates near the probe atoms and the magnitude of the displacements of the latter have been derived from the Mossbauer data by means of a model describing the behaviour of the Mossbauer patterns under the influence of time-dependent electric field gradients and probe positions.