title: Communication: Infrared spectroscopy of salt-water complexes.
abstract: To explore how the ion-pair in a single salt molecule evolves with the addition of water, infrared (IR) spectra of complexes composed of NaCl and multiple water molecules have been recorded for the first time. The NaCl(H2O)n complexes were formed and probed in liquid helium nanodroplets, and IR spectra were recorded for n = 1 → 4. The spectra for n = 1, 2, and 3 are consistent with formation of the lowest energy contact-ion pair structures in which each water molecule forms a single ionic hydrogen bond to an intact Na(+)Cl(-) ion-pair. Alternative structures with hydrogen bonding between water molecules become energetically competitive for n = 4, and the IR spectrum indicates likely the coexistence of at least two isomers.
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Jon
authors.initials: J
authors.lastname: Tandy
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Cheng
authors.initials: C
authors.lastname: Feng
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Adrian
authors.initials: A
authors.lastname: Boatwright
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Gautam
authors.initials: G
authors.lastname: Sarma
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Sadoon
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Shirley
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Natercia Das Neves
authors.initials: ND
authors.lastname: Rodrigues
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Ethan M
authors.initials: EM
authors.lastname: Cunningham
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Shengfu
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Ellis