Concentration and temperature dependence of hydrogen vibrations along thecaxis for hydrogen in yttrium: Evidence of dynamically coupled hydrogen pairs

Abstract

The c-axis vibrations of hydrogen in yttrium have been measured at various concentrations and temperatures using high-resolution neutron spectroscopy. The unusual splitting of these modes is revealed to be highly sensitive to both conditions and to isotopic dilution. The results indicate that the splitting is caused by hydrogen pairs dynamically coupled across metal atoms and that this interaction is modulated by concentration- and temperature-dependent occupation correlations along the c axis.