Emergence of an Icosahedral (H2)13 Cluster inside a Pure Silica Faujasite

Abstract

We report the structuration of H₂ inside the faujasite DAY, obtained by ab initio molecular dynamics simulations at 20, 40, and 77 K. Here is detailed how the environment adjusts the rotational and vibrational modes of molecular hydrogen; also, we show the process by which the hindered rotor is altered by the temperature. By loading the faujasite with H₂, the electrical field of the host structure enhances orientational intermolecular interactions of the adsorbate molecules. The structural analysis shows an organized H₂ layer at the walls of the zeolite supercages. This organization facilitates the clustering of the non-absorbed dihydrogens. The observed cluster reminds astonishingly of the icosahedral (H₂)₁₃ structure, obtained for dihydrogen at high pressures (≈10⁵ bar). In this work, we detail the physicochemical mechanisms leading to such a structured cluster.