title: Time-resolved observation of the Eigen cation in liquid water.
abstract: Experimental observation and time relaxation measurement of the hydrated proton Eigen form [H(3)O(+)(H(2)O)(3)] are presented here. Vibrational time-resolved spectroscopy is used with an original method of investigating the proton excess in water. The anharmonicity of the time-resolved spectra is characteristic of the Eigen-type proton geometry. Proton relaxation occurs in less than 200 fs. A calculation of the potential energy confirms the experimental result and the Eigen cation lifetime is in good agreement with previous molecular dynamics simulations.
authors.affiliation: Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, 91128 Palaiseau, France.
authors.forename: Wafa
authors.initials: W
authors.lastname: Amir
authors.forename: Guilhem
authors.initials: G
authors.lastname: Gallot
authors.forename: François
authors.initials: F
authors.lastname: Hache
authors.forename: S
authors.initials: S
authors.lastname: Bratos
authors.forename: J-C
authors.initials: JC
authors.lastname: Leicknam
authors.forename: R
authors.initials: R
authors.lastname: Vuilleumier
mesh_terms: D002412:Cations; D002627:Chemistry, Physical / Q000379:methods*; D015233:Models, Statistical; D008968:Molecular Conformation; D016011:Normal Distribution; D010100:Oxygen / Q000737:chemistry; D011522:Protons; D012997:Solvents; D013055:Spectrophotometry, Infrared; D013057:Spectrum Analysis / Q000379:methods*; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D002412:Cations; D011522:Protons; D012997:Solvents; D014867:Water; D010100:Oxygen