title: Manifestations of Torsion-CH Stretch Coupling in the Infrared Spectrum of CH3OO.
abstract: With a step-scan Fourier-transform spectrometer we recorded temporally resolved infrared absorption spectra of CH3OO radicals that were produced upon irradiation of CH3COCH3 and O2 at 193 nm in a flowing mixture. At a resolution of 0.15 cm(-1), the rotational structure of the ν2 band of CH3OO near 2954.4 cm(-1) is partially resolved and shows an unexpectedly broadened, and somewhat distorted, Q-branch. A 4D model Hamiltonian, consisting of three CH stretches and the methyl torsion, was developed to explore the origins of this broadening. The vibrational progressions predicted by the model Hamiltonian and the rotational contours of the ν2 band, based on experimental ground-state rotational parameters and their values scaled by their calculated ratios for the upper state, produced simulations in satisfactory agreement with the observed spectrum. These results provide new insight into the vibrational couplings in CH3OO.
authors.affiliation: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University , 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan.
authors.forename: Kuo-Hsiang
authors.initials: KH
authors.lastname: Hsu
authors.affiliation: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University , 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan.
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Huang
authors.affiliation: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University , 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan.|Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan.
authors.forename: Yuan-Pern
authors.initials: YP
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States.
authors.forename: Meng
authors.initials: M
authors.lastname: Huang
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States.
authors.forename: Terry A
authors.initials: TA
authors.lastname: Miller
authors.affiliation: Department of Chemistry, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Anne B
authors.initials: AB
authors.lastname: McCoy