A coherent quasielastic neutron scattering study of NO3 ion motion in molten RbNO3

Quasielastic neutron scattering experiments have been performed on molten RbNO₃, The quasielastic spectra are composed of narrow and broad coherent components. The narrow component is assigned to the translational motion due to the diffusion of the center of gravity of each ion. The broad component corresponds to fast intra-ionic motions within the nitrate ion. From the momentum dependence of the broad component, it is concluded that the nitrate ion in molten RbNO₃ is mainly subjected to a rotational vibration centered around the C₃ axis and that the form of the nitrate motion around C₃ axis does not change with increasing temperature.