Abstract
Recently, for the first time a hydrate clathrate was discovered with hydrogen. Aside from the great technological promise that is inherent in storing hydrogen at high density at modest pressures, there is great scientific interest as this would constitute the first hydrate clathrate with multiple species per cage. The multiple cage occupancy is controversial, and reproducibility of the experiments has been questioned. Therefore, in this study we try to illucidate the stability of the hydrogen hydrate clathrate, and determine the thermodynamically most favored cage occupancy using highly accurate ab initio computer simulations.