title: Acetonitrile cluster solvation in a cryogenic ethane-methane-propane liquid: Implications for Titan lake chemistry.
abstract: The atmosphere of Titan, Saturn's largest moon, exhibits interesting UV- and radiation-driven chemistry between nitrogen and methane, resulting in dipolar, nitrile-containing molecules. The assembly and subsequent solvation of such molecules in the alkane lakes and seas found on the moon's surface are of particular interest for investigating the possibility of prebiotic chemistry in Titan's hydrophobic seas. Here we characterize the solvation of acetonitrile, a product of Titan's atmospheric radiation chemistry tentatively detected on Titan's surface [H. B. Niemann et al., Nature 438, 779-784 (2005)], in an alkane mixture estimated to match a postulated composition of the smaller lakes during cycles of active drying and rewetting. Molecular dynamics simulations are employed to determine the potential of mean force of acetonitrile (CH3CN) clusters moving from the alkane vapor into the bulk liquid. We find that the clusters prefer the alkane liquid to the vapor and do not dissociate in the bulk liquid. This opens up the possibility that acetonitrile-based microscopic polar chemistry may be possible in the otherwise nonpolar Titan lakes.
authors.affiliation: Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: L René
authors.identifier: 0000000150849190
authors.initials: LR
authors.lastname: Corrales
authors.affiliation: Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Yi
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Samantha K
authors.initials: SK
authors.lastname: Trumbo
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: David
authors.initials: D
authors.lastname: Shalloway
authors.affiliation: Carl Sagan Institute and Department of Astronomy, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Lunine
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Usher