The photodissociation of oxetane at 193 nm as the reverse of the Paterno-Buchi reaction

Journal Article · Mon Dec 14 00:00:00 EST 2009 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3270162· OSTI ID:21559814

Lee, Shih-Huang ^[1]

---

1. National Synchrotron Radiation Research Center (NSRRC), 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China)

We investigated the photodissociation of oxetane (1,3-trimethylene oxide) at 193.3 nm in a molecular-beam apparatus using photofragment-translational spectroscopy and selective photoionization. We measured time-of-flight (TOF) spectra and angular anisotropy parameters {beta}(t) as a function of flight time of products at m/z=26-30 u utilizing photoionization energies from 9.8 to 14.8 eV. The TOF distributions of the products alter greatly with the employed photon energy, whereas their {beta}(t) distributions are insensitive to the photon energy. Dissociation to H{sub 2}CO+C{sub 2}H{sub 4} is the major channel in the title reaction. Three distinct dissociation paths with branching ratios 0.923:0.058:0.019 are responsible for the three features observed in the distribution of kinetic energy released in the channel H{sub 2}CO+C{sub 2}H{sub 4}. The observation of H{sub 2} and H atoms, {approx}1% in branching, indicates that products H{sub 2}CO and C{sub 2}H{sub 4} spontaneously decompose to only a small extent. Most HCO, C{sub 2}H{sub 3}, and C{sub 2}H{sub 2} ions originate from dissociative photoionization of products H{sub 2}CO and C{sub 2}H{sub 4}. Except atomic H and H{sub 2}, the photoproducts have large angular anisotropies, {beta}{>=}-0.8, which reflects rapid dissociation of oxetane following optical excitation at 193.3 nm. The mechanisms of dissociation of oxetane are addressed. Our results confirm the quantum-chemical calculations of Palmer et al. and provide profound insight into the Paterno-Buchi reaction.

• OSTI ID: 21559814
• Journal Information: Journal of Chemical Physics, Vol. 131, Issue 22; Other Information: DOI: 10.1063/1.3270162; (c) 2009 American Institute of Physics; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANISOTROPY
ATOMS
BRANCHING RATIO
CHEMISTRY
DISSOCIATION
DISTRIBUTION
ETHERS
ETHYLENE
EXCITATION
HETEROCYCLIC OXYGEN COMPOUNDS
HYDROGEN
KINETIC ENERGY
MOLECULAR BEAMS
PHOTOIONIZATION
PHOTOLYSIS
PHOTONS
REACTION KINETICS
SPECTROSCOPY
TIME-OF-FLIGHT METHOD
VINYL RADICALS
ALKENES
ALKYL RADICALS
BEAMS
BOSONS
CHEMICAL REACTIONS
DECOMPOSITION
DIMENSIONLESS NUMBERS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY
ENERGY-LEVEL TRANSITIONS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
IONIZATION
KINETICS
MASSLESS PARTICLES
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADICALS