Neutron diffraction from liquid hydrogen bromide: Study of the orientational correlations

Publisher Website
Google Scholar
Abstract
The three partial structure factors of liquid hydrogen bromide along the coexistence curve have been measured by neutron diffraction using the isotopic substitution technique. The structure factors and corresponding pair correlation functions obtained suggest that it is an excellent approximation to regard the bromine atom as the center of mass of the hydrogen bromide molecule. The anisotropic terms in the intermolecular potential manifest themselves primarily by causing a significant degree of correlation between the orientations of neighboring molecules. In order to gauge the size of these orientational correlations an image reconstruction technique is employed. This analysis shows that there is a pronounced correlation between the relative orientations of neighboring molecules, but that there is not a strong directionality in the local coordination of any particular molecule. The results are discussed in relation to a previous experiment on hydrogen bromide which proposed the formation of hydrogen bonds in this liquid.