title: Reactive and Inelastic Channels in the Ca*···FCH3 Transition State: A Simple Branching Mechanism.
abstract: To study the excited state dynamics between a calcium atom and the CH3F molecule, a Ca···CH3F 1:1 complex has been prepared by a supersonic expansion with laser ablation of calcium metal in the gas phase. Tunable laser excitation of these complexes in molecular states correlating to Ca (1)P1(4s4p) + CH3F allows observing two competitive channels: the direct dissociation and the reactive channel into CaF* + CH3. The translational recoil, as well as the alignment of the fragments Ca* and CaF* have been analyzed by velocity map imaging and time-of-flight mass spectrometry. This revealed that both the dissociation and reaction processes are quasi direct and are of comparable intensity. We provide a simple interpretation for this process: the electronically excited potential surface of the Ca*···FCH3 complex initiates a fast predissociation from a suspended well to two repulsive surfaces that lead either to Ca (1)P1(4s4p) (Ω = 1) + CH3F or to CaF((2)Δ) + CH3.
authors.forename: M
authors.initials: M
authors.lastname: Briant
authors.forename: E
authors.initials: E
authors.lastname: Gloaguen
authors.affiliation: §LCAR IRSAMC, Université de Toulouse 3, F-31062 Toulouse, France.
authors.forename: A
authors.initials: A
authors.lastname: Beswick
authors.forename: J M
authors.initials: JM
authors.lastname: Mestdagh
authors.affiliation: ∥Institute of Atomic and Molecular Physics, Jilin University, Changchun, 1300012, China.|⊥Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Stolte
authors.forename: L
authors.initials: L
authors.lastname: Poisson
authors.forename: C
authors.initials: C
authors.lastname: Pothier
authors.forename: B
authors.initials: B
authors.lastname: Soep