title: Thermodynamics of water dimer dissociation in the primary hydration shell of the iodide ion with temperature-dependent vibrational predissociation spectroscopy.
abstract: The strong temperature dependence of the I(-)·(H2O)2 vibrational predissociation spectrum is traced to the intracluster dissociation of the ion-bound water dimer into independent water monomers that remain tethered to the ion. The thermodynamics of this process is determined using van't Hoff analysis of key features that quantify the relative populations of H-bonded and independent water molecules. The dissociation enthalpy of the isolated water dimer is thus observed to be reduced by roughly a factor of three upon attachment to the ion. The cause of this reduction is explored with electronic structure calculations of the potential energy profile for dissociation of the dimer, which suggest that both reduction of the intrinsic binding energy and vibrational zero-point effects act to weaken the intermolecular interaction between the water molecules in the first hydration shell. Additional insights are obtained by analyzing how classical trajectories of the I(-)·(H2O)2 system sample the extended potential energy surface with increasing temperature.
authors: Sterling Chemistry Laboratory, Yale University , New Haven, Connecticut 06525, United States.
authors: Conrad T
authors: CT
authors: Wolke
authors: Fabian S
authors: FS
authors: Menges
authors: Niklas
authors: N
authors: Tötsch
authors: Olga
authors: O
authors: Gorlova
authors: Joseph A
authors: JA
authors: Fournier
authors: Gary H
authors: GH
authors: Weddle
authors: Mark A
authors: MA
authors: Johnson
authors: Nadja
authors: N
authors: Heine
authors: Tim K
authors: TK
authors: Esser
authors: Harald
authors: H
authors: Knorke
authors: Knut R
authors: KR
authors: Asmis
authors: Anne B
authors: AB
authors: McCoy
authors: Daniel J
authors: DJ
authors: Arismendi-Arrieta
authors: Rita
authors: R
authors: Prosmiti
authors: Francesco
authors: F
authors: Paesani