Non covalent interactions in gas clathrates

F. Izquierdo
Universidad de Oviedo, Oviedo, Espagne.

Vendredi 23 Mai 2014, 11^h00
bibliothèque LCT, tour 12 - 13, 4e étage

DFT calculations have been performed to study the sI-type clathrate hydrate with CO₂ and CH₄ molecules. Periodical and cluster (with the crystalline optimized geometry) calculations were performed to study the energetic stability and orientation in 5¹² (pentagonal) and 5¹²6² (hexagonal) cages. The XDM, exchange-hole dipole moment, method was used to include the dispersion interactions. The most important forces that maintain the clathrates structures are the non covalent interactions, using NCIPLOT and CRITIC2 we study these interactions in both the periodic and cluster approximation and the influence of pressure and orientation of the guest molecule inside the cage. The current results suggest that there is no interaction between guest molecules of different cages, the most stable orientation is the one that minimizes the repulsion and maximizes the continuity of the Van der Waals interactions. The effect of the electrostatic potential is also under study.