title: Hydrogen peroxide and ammonia on protonated ice clusters.
abstract: A temperature controlled source for protonated water clusters has been combined with high-resolution mass spectroscopy to study the stability pattern of ice clusters and compounds with ammonia and hydrogen peroxide depending on temperature. The stability pattern of pure protonated ice shows the two well known peaks at 21 and 28 molecules and also less pronounced structure up to n=55. Ammonia and hydrogen peroxide do not destroy this pattern but shift it by a number of water molecules. The additives are therefore integrated in the persisting crystalline structure of the pure protonated ice. Based on this structural information, density functional theory calculations reveal that hydrogen peroxide and ammonia occupy surface positions on a dodecahedral 21-molecule cluster and are not caged in the center.
authors.affiliation: Laboratoire Aimé Cotton, CNRS, Bâtiment 505, Université Paris sud, 91405 Orsay Cedex, France. martin.schmidt@lac.u-psud.fr
authors.forename: Martin
authors.initials: M
authors.lastname: Schmidt
authors.forename: Albert
authors.initials: A
authors.lastname: Masson
authors.forename: Catherine
authors.initials: C
authors.lastname: Bréchignac
authors.forename: Hai-Ping
authors.initials: HP
authors.lastname: Cheng
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D003198:Computer Simulation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007053:Ice; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011522:Protons
chemical_list: D007053:Ice; D011522:Protons; D000641:Ammonia; D006861:Hydrogen Peroxide