Ab initio energetics and kinetics study of H_2 and CH_4 in the SI Clathrate Hydrate

TL;DR

This study uses ab initio density functional theory to analyze the energetics and diffusion pathways of H_2 and CH_4 molecules within SI clathrate hydrate structures, providing detailed energy landscapes and structural data.

Contribution

It offers new ab initio insights into the energy landscape and diffusion barriers of H_2 and CH_4 in SI clathrate hydrate, expanding on previous work with additional structural and energetic details.

Findings

Energy barriers for H_2 and CH_4 diffusion paths identified

Detailed energy landscape of guest molecules in hydrate cages provided

Structural data for multiple hydrate phases reported

Abstract

We present ab initio results at the density functional theory level for the energetics and kinetics of H_2 and CH_4 in the SI clathrate hydrate. Our results complement a recent article by some of the authors [G. Roman-Perez et al., Phys. Rev. Lett. 105, 145901 (2010)] in that we show additional results of the energy landscape of H_2 and CH_4 in the various cages of the host material, as well as further results for energy barriers for all possible diffusion paths of H_2 and CH_4 through the water framework. We also report structural data of the low-pressure phase SI and the higher-pressure phases SII and SH.