Jump to main content
Jump to site search


Sequential evaporation of water molecules from protonated water clusters: measurement of the velocity distributions of the evaporated molecules and statistical analysis

Abstract

Velocity distributions of water molecules evaporated from protonated water clusters H+(H2O)n≤ 10 after collision-induced dissociation (CID) were measured using the combined correlated ion and neutral fragment time-of-flight (COINTOF) and velocity map imaging (VMI) techniques. As observed previously, all measured velocity distributions exhibit two contributions, with a low velocity part identified by statistical molecular dynamics (SMD) simulations as events obeying the Maxwell-Boltzmann statistics and a high velocity contribution corresponding to non ergodic events in which energy redistribution is incomplete. In contrast to earlier studies, where the evaporation of a single molecule was probed, the present study is concerned with events involving the evaporation of up to five water molecules. In particular, we discuss here in details the cases of two and three evaporated molecules, respectively. Evaporation of several water molecules after CID can be interpreted in general as a sequential evaporation process. In addition to the SMD calculations, a Monte Carlo (MC) based simulation was developed allowing the reconstruction of the velocity distribution produced by the evaporation of m molecules from H+(H2O)n≤ 10 cluster ions using the measured velocity distributions singly evaporated molecules as the input. The observed broadening of the low-velocity part of the distributions for the evaporation of two and three molecules as compared to the width for the evaporation of a single molecule results from the cumulative recoil velocity of the successive ion residues as well as the intrinsically broader distributions for decreasingly smaller parent clusters. Further MC simulations were carried out assuming that a certain proportion of non-ergodic events is responsible for the first evaporation in such a sequential evaporation series, thereby allowing to model the entire velocity distribution.

Back to tab navigation

Publication details

The article was received on 26 Apr 2018, accepted on 13 Jun 2018 and first published on 13 Jun 2018


Article type: Paper
DOI: 10.1039/C8CP02657B
Citation: Phys. Chem. Chem. Phys., 2018, Accepted Manuscript
  •   Request permissions

    Sequential evaporation of water molecules from protonated water clusters: measurement of the velocity distributions of the evaporated molecules and statistical analysis

    F. Berthias, L. Feketeova, H. Abdoul-Carime, F. Calvo, B. Farizon, M. Farizon and T. D. Märk, Phys. Chem. Chem. Phys., 2018, Accepted Manuscript , DOI: 10.1039/C8CP02657B

Search articles by author

Spotlight

Advertisements