title: Simulations and spectra of water in CO matrices.
abstract: Models for the inclusion of water molecules in carbon monoxide matrices are developed using density functional theory applied to amorphous solid systems. The models cover a large range of systems for smaller or larger CO matrices with different water content, consisting of either individual H2O molecules or small clusters linked by H-bonds. The vibrational spectra of the samples are predicted at the minimum of their potential energy surface. The spectra allow instances where the water molecules remain isolated or form aggregates to be discerned, and they also provide an indication of the strength of the H-bonding, when present. The calculations support recent experimental observations that linked IR bands at 3707 cm-1and 3617 cm-1to the presence of unbound water molecules in water-poor CO/H2O mixed ices. Assignment of some observed bands to water dimers or trimers is suggested as well. The residual static pressure in fixed-volume simulation cells is also calculated.
authors.affiliation: Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, 28006 Madrid, Spain. rafael.escribano@csic.es.
authors.forename: Rafael
authors.identifier: http://orcid.org/0000-0002-3048-9420
authors.initials: R
authors.lastname: Escribano
authors.affiliation: CIC Nanogune and DIPC, Tolosa Hiribidea 76, 20018 San Sebastian, Spain and Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain and Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, J. J. Thomson Ave, Cambridge CB3 0HE, UK.
authors.forename: Emilio
authors.initials: E
authors.lastname: Artacho
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kouchi
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: Tetusya
authors.initials: T
authors.lastname: Hama
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: Yuki
authors.identifier: http://orcid.org/0000-0002-9218-7663
authors.initials: Y
authors.lastname: Kimura
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hidaka
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Watanabe