title: The roaming atom: straying from the reaction path in formaldehyde decomposition.
abstract: We present a combined experimental and theoretical investigation of formaldehyde (H2CO) dissociation to H2 and CO at energies just above the threshold for competing H elimination. High-resolution state-resolved imaging measurements of the CO velocity distributions reveal two dissociation pathways. The first proceeds through a well-established transition state to produce rotationally excited CO and vibrationally cold H2. The second dissociation pathway yields rotationally cold CO in conjunction with highly vibrationally excited H2. Quasi-classical trajectory calculations performed on a global potential energy surface for H2CO suggest that this second channel represents an intramolecular hydrogen abstraction mechanism: One hydrogen atom explores large regions of the potential energy surface before bonding with the second H atom, bypassing the saddle point entirely.
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: D
authors.initials: D
authors.lastname: Townsend
authors.forename: S A
authors.initials: SA
authors.lastname: Lahankar
authors.forename: S K
authors.initials: SK
authors.lastname: Lee
authors.forename: S D
authors.initials: SD
authors.lastname: Chambreau
authors.forename: A G
authors.initials: AG
authors.lastname: Suits
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Rheinecker
authors.forename: L B
authors.initials: LB
authors.lastname: Harding
authors.forename: J M
authors.initials: JM
authors.lastname: Bowman