title: Structural and spectroscopic properties of water around small hydrophobic solutes.
abstract: We investigated the structural, dynamical and spectroscopic properties of water molecules around a solvated methane by means of Car-Parrinello molecular dynamics simulations. Despite their mobility, in the first shell, water molecules are dynamically displaced in a clathrate-like cage around the hydrophobic solute. No significant differences in water geometrical parameters, in molecular dipole moments or in hydrogen bonding properties, are observed between in-shell and out-shell molecules, indicating that liquid water can accommodate a small hydrophobic solute without altering its structural properties. The calculated contribution of the first-shell water molecules to the infrared spectra does not show significant differences with respect the bulk signal once the effects of the missing polarization of second-shell molecules has been taken into account. Small fingerprints of the clathrate-like structure appear in the vibrational density of states in the libration and OH stretching regions.
authors.affiliation: Dipartimento di Matematica Pura e Applicata, Università degli studi dell'Aquila, via Vetoio 1, 67010, L'Aquila, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Montagna
authors.forename: Fabio
authors.initials: F
authors.lastname: Sterpone
authors.forename: Leonardo
authors.initials: L
authors.lastname: Guidoni
mesh_terms: D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008697:Methane / Q000737:chemistry*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D013055:Spectrophotometry, Infrared; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D008697:Methane