Hyperthermal surface-collisions of water cluster cations
Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Str. 2, 12489 Berlin, Germany
2 Tel Aviv University, Sackler Faculty of Exact Sciences, School of Chemistry, Ramat Aviv, Tel Aviv 69978, Israel
Corresponding author: a email@example.com
Published online: 3 July 2003
Size-selected, protonated water cluster cations (H2O)nH+, , are scattered at normal incidence from the surface of a diamond-coated silicon wafer at collision energies eV. The size distribution of collision-induced fragment-ions and the ion yield of scattered particles are analyzed, using a secondary time-of-flight mass spectrometer, as a function of the cluster size, n, and the collision energy, . Even at low impact energies only very small fragment-ions can be detected, with a maximum fragment size of ~35% of the colliding parent cluster ions. For clusters consisting of more than 10 molecules, the protonated water dimer (H2O)2H+ becomes the predominant fragment-ion. The total charge survival yield obeys a nonlinear increase with cluster size; for the largest clusters investigated, more than 35% of the impacting ions survive the surface collision in the cationic charge state.
PACS: 34.30.+h – Intramolecular energy transfer; intramolecular dynamics; dynamics of van der Waals molecules / 34.50.-s – Scattering of atoms and molecules / 34.70.+e – Charge transfer / 36.40.-c – Atomic and molecular clusters / 61.46.+w – Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals / 82.40.-g – Chemical kinetics and reactions: special regimes and techniques
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003