title: Structural Properties and Dynamics of Thiophene in Sub/Supercritical Carbon Dioxide from Car-Parrinello Molecular Dynamics Simulations.
abstract: Structrual and dynamic properties of thiophene (C4H4S) in supercritical carbon dioxide were studied using Car-Parrinello molecular dynamics simulations. The geometries and energies optimized for the thiophene-CO2 complex show a stable C-H···O hydrogen bond interactions both in gas phase and in supercritical CO2. The radial distribution functions of CO2 around thiophene in the supercritical phase state show a correlation suggesting C-H···O hydrogen bond and S···C interaction. Local structural properties of the mixtures were investigated by angular-radial distributions and spatial distribution functions. The results show a mutually parallel arrangement between the thiophene plane and CO2 molecules at short distances and a high probability of the thiophene being located in the radial directions of the CO2 molecules. The decay of orientational correlations at 318.15 K shows slower relaxation compared to those of 298.15 K for first and second rank correlations. The vibrations of CO2 and thiophene molecules have been examined through an analysis of the velocity autocorrelation functions of the atoms. The C-H stretching modes of thiophene in the isolated configuration are less red-shifted and have a much narrower frequency range than that in the mixtures.
authors.affiliation: †College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, China.
authors.forename: Yongping
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: †College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, China.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Wang
authors.affiliation: ||Guodian Science and Technology Research Institute, Nanjing, 210031, China.
authors.forename: Yueyang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: †College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, China.
authors.forename: WenLin
authors.initials: W
authors.lastname: Xu
authors.affiliation: ‡State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University), Nanjing, 211816, China.
authors.forename: Shengui
authors.initials: S
authors.lastname: Ju