title: Gas-phase VUV photoionisation and photofragmentation of the silver deuteride nanocluster [Ag10D8L6](2+) (L = bis(diphenylphosphino)methane). A joint experimental and theoretical study.
abstract: The bis(diphenylphosphino)methane (L = Ph2PCH2PPh2) ligated silver deuteride nanocluster dication, [Ag10D8L6](2+), has been synthesised in the condensed phase via the reaction of bis(diphenylphosphino)methane, silver nitrate and sodium borodeuteride in the methanol : chloroform (1 : 1) mixed solvent system. The photoionisation and photofragmentation of this mass-selected cluster were studied using a linear ion trap coupled to the DESIRS VUV beamline of the SOLEIL Synchrotron. At 15.5 eV the main ionic products observed are [Ag10D8L5](2+), [Ag10D8L4](2+), [Ag10D8L6](3+)˙, [Ag9D8L4](2+)˙, and [AgL2](+). The later two products arise from fragmentation of [Ag10D8L6](3+)˙. An analysis of the yields of these product ions as a function of the photon energy reveals the onset for the formation of [AgL2](+) and [Ag9D8L4](2+)˙ is around 2 eV higher than that for ionisation to produce [Ag10D8L5](3+)˙. The onset of ionisation energy of [Ag10D8L6](2+) was determined to be 9.3 ± 0.3 eV from a fit of the yield of the product ion, [Ag10D8L6](3+)˙, as a function of the VUV photon energy. DFT calculations at the RI-PBE/RECP-def2-SVP level of theory were carried out to search for a possible structure of the cluster and to estimate its vertical and adiabatic ionisation energies. The calculated lowest energy structure of the [Ag10D8L6](2+) nanocluster contains a symmetrical bicapped square antiprism as a silver core in which hydrides are located as a mix of triangular faces and edges. Four of the bisphosphines bind to the edges of the cluster core as bidentate ligands, the remaining two bisphosphines bind via a single phosphorus donor atom to each of the apical silver atoms. The DFT calculated adiabatic ionisation energy for this structure is 8.54 eV, in satisfactory agreement with experiment.
authors.affiliation: Institut Lumière Matière, Université Claude Bernard Lyon 1, CNRS UMR 5306, Lyon, France. philippe.dugourd@univ-lyon1.fr.
authors.forename: Steven
authors.initials: S
authors.lastname: Daly
authors.forename: Marjan
authors.initials: M
authors.lastname: Krstić
authors.forename: Alexandre
authors.initials: A
authors.lastname: Giuliani
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Antoine
authors.forename: Laurent
authors.initials: L
authors.lastname: Nahon
authors.forename: Athanasios
authors.initials: A
authors.lastname: Zavras
authors.forename: George N
authors.initials: GN
authors.lastname: Khairallah
authors.forename: Vlasta
authors.initials: V
authors.lastname: Bonačić-Koutecký
authors.forename: Philippe
authors.initials: P
authors.lastname: Dugourd
authors.forename: Richard A J
authors.initials: RA
authors.lastname: O'Hair
mesh_terms: D001555:Benzene Derivatives / Q000737:chemistry*; D003903:Deuterium / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives*; D008958:Models, Molecular; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010782:Photolysis; D012834:Silver / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D014466:Ultraviolet Rays
chemical_list: D001555:Benzene Derivatives; D005740:Gases; D007477:Ions; D009943:Organophosphorus Compounds; C519090:phosphinine; D012834:Silver; D003903:Deuterium; D008697:Methane