title: Photodissociation of CH3CHO at 248 nm by time-resolved Fourier-transform infrared emission spectroscopy: verification of roaming and triple fragmentation.
abstract: By using time-resolved Fourier-transform infrared emission spectroscopy, the HCO fragment dissociated from acetaldehyde (CH3CHO) at 248 nm is found to partially decompose to H and CO. The fragment yields are enhanced by the Ar addition that facilitates the collision-induced internal conversion. The channels to CH2CO + H2 and CH3CO + H are not detected significantly. The rotational population distribution of CO, after removing the Ar collision effect, shows a bimodal feature comprising both low- and high-rotational (J) components, sharing a fraction of 19% and 81%, respectively, for the vibrational state v = 1. The low-J component is ascribed to both roaming pathway and triple fragmentation. They are determined to have a branching ratio of <0.13 and >0.06, respectively, relative to the whole v = 1 population. The CO roaming is accompanied by a highly vibrational population of CH4 that yields a vibrational bimodality.
authors: Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
authors: Kai-Chan
authors: KC
authors: Hung
authors: Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
authors: Po-Yu
authors: PY
authors: Tsai
authors: Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
authors: Hou-Kuan
authors: HK
authors: Li
authors: Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
authors: King-Chuen
authors: KC
authors: Lin