title: Kinetic study of the reaction of vanadium and vanadium-titanium oxide cluster anions with SO2.
abstract: The reactivity of mass-selected V(4)O(10)(-) cluster anions towards sulphur dioxide is investigated in an ion trap under multi-collision conditions. Gas phase reaction kinetics are studied as a function of temperature (T(R) = 150-275 K). The binding energy of SO(2) to V(4)O(10)(-) is obtained by analyzing the experimental low pressure rate constants, employing the Lindemann energy transfer model for association reactions in conjunction with statistical RRKM theory. In addition, infrared multiple photon dissociation spectroscopy is used in conjunction with density functional theory for the structural assignment of the [V(4)O(10)(-), SO(2)] complex, revealing a square pyramidal structure with the SO(2) molecule incorporated in the vanadium oxide framework. Energy profiles are calculated for the reaction between V(4)O(10)(-) and V(6)O(15)(-) with SO(2). Whereas the transition structures along the reaction pathway of V(4)O(10)(-) with SO(2) have energies below those of the separated partners, the reaction of V(6)O(15)(-) with SO(2) proceeds via a transition structure with energy higher than the educts. The role of cluster size and composition is investigated by studying the reaction kinetics of larger (V(6)O(15)(-) and V(8)O(20)(-)) and titanium doped (V(3)TiO(10)(-) and V(2)Ti(2)O(10)(-)) vanadium oxide clusters with SO(2). The observed cluster size and composition dependencies are discussed.
authors.affiliation: Laboratorium voor Vaste-Stoffysica en Magnetisme, KU Leuven, Belgium. ewald.janssens@fys.kuleuven.be
authors.forename: Ewald
authors.initials: E
authors.lastname: Janssens
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Lang
authors.forename: Mathias
authors.initials: M
authors.lastname: Brümmer
authors.forename: Andrzej
authors.initials: A
authors.lastname: Niedziela
authors.forename: Gabriele
authors.initials: G
authors.lastname: Santambrogio
authors.forename: Knut R
authors.initials: KR
authors.lastname: Asmis
authors.forename: Joachim
authors.initials: J
authors.lastname: Sauer