title: Computational study of the interplay between intermolecular interactions and CO2orientations in type I hydrates.
abstract: Carbon dioxide (CO2) molecules show a rich orientation landscape when they are enclathrated in type I hydrates. Previous studies have described experimentally their preferential orientations, and some theoretical works have explained, but only partially, these experimental results. In the present paper, we use classical molecular dynamics and electronic density functional theory to advance in the theoretical description of CO2orientations within type I hydrates. Our results are fully compatible with those previously reported, both theoretical and experimental, the geometric shape of the cavities in hydrate being, and therefore, the steric constraints, responsible for some (but not all) preferential angles. In addition, our calculations also show that guest-guest interactions in neighbouring cages are a key factor to explain the remaining experimental angles. Besides the implication concerning equation of state hydrate modeling approximations, the conclusion is that these guest-guest interactions should not be neglected, contrary to the usual practice.
authors.affiliation: Dpto. de Física Aplicada, Fac. de Ciencias, Univ. de Vigo, E36310, Spain. mmpineiro@uvigo.es.
authors.forename: M
authors.initials: M
authors.lastname: Pérez-Rodríguez
authors.affiliation: Dpto. de Física Aplicada, Fac. de Ciencias, Univ. de Vigo, E36310, Spain. mmpineiro@uvigo.es.
authors.forename: A
authors.initials: A
authors.lastname: Vidal-Vidal
authors.affiliation: Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, E21071 Huelva, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Míguez
authors.affiliation: Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, E21071 Huelva, Spain.
authors.forename: F J
authors.initials: FJ
authors.lastname: Blas
authors.affiliation: UMR 5150 - Laboratoire des Fluides Complexes et leurs Réservoirs, Université de Pau et des Pays de l'Adour, B. P. 1155, Pau, Cedex 64013, France.
authors.forename: J-P
authors.initials: JP
authors.lastname: Torré
authors.affiliation: Dpto. de Física Aplicada, Fac. de Ciencias, Univ. de Vigo, E36310, Spain. mmpineiro@uvigo.es.
authors.forename: M M
authors.initials: MM
authors.lastname: Piñeiro