Umbertoluca Ranieri, Leonardo Del Rosso, Livia Eleonora Bove, Milva Celli, Daniele Colognesi, Richard Gaal, Thomas C Hansen, Michael Marek Koza, Lorenzo Ulivi
Hydrogen clathrate hydrates are ice-like crystalline substances in which hydrogen molecules are trapped inside polyhedral cages formed by the water molecules. Small cages can host only a single H2 molecule, while each large cage can be occupied by up to four H2 molecules. Here, we present a neutron scattering study on the structure of the sII hydrogen clathrate hydrate and on the low-temperature dynamics of the hydrogen molecules trapped in its large cages, as a function of the gas content in the samples. We observe spectral features at low energy transfer (between 1 and 3 meV), and we show that they can be successfully assigned to the rattling motion of a single hydrogen molecule occupying a large water cage...
April 28, 2024: Journal of Chemical Physics