Ultraviolet photodissociation dynamics of 2-methylallyl radical from the 3p Rydberg state were investigated in the wavelength region of 226–244 nm using the high-n Rydberg atom time-of-flight (HRTOF) technique. The 2-methylallyl radicals were generated by 193 nm photolysis of 3-chloro-2-methyl-1-propene precursors. The photofragment yield spectrum of H-atom products increases in intensity with decreasing wavelengths in 226–244 nm. The TOF spectra of H-atom products show a bimodal structure. The predominant product channel (with ∼98% branching ratio) has a kinetic energy release peaking at ∼7 kcal/mol, with an average ratio of ET in the total available energy, (fT), of ∼0.18 in 226–244 nm and an isotropic product angular distribution. At the low ET, isotropic component is from statistical unimolecular decomposition of highly vibrationally excited hot 2-methylallyl to the methylenecyclopropane+H products, following internal conversion from the excited electronic state. The minor product channel (with ∼2% branching ratio) has a large kinetic energy peaking at ∼50 kcal/mol, with (fT)≈0.63 and an anisotropic angular distribution (β≈−0.2). At the high ET, anisotropic component is non-statistical and is postulated to be from direct loss of H atom via the 3p Rydberg state or repulsive part of the ground state to the 1,3-butadiene+H products.
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Photodissociation of HCO radical via Ã2A″ state: Accurate determination of bond dissociation energy D0(H–CO)
The photodissociation dynamics of jet-cooled HCO radical was investigated in the region of 490 nm to 715 nm using the H-atom high-n Rydberg time-of-flight (HRTOF) technique. The CO product rovibrational state populations are well resolved in the H + CO product translational energy distributions, and an accurate H–C bond dissociation energy D0(H–CO) = 5086 ± 5 cm−1 is obtained.
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- Award ID(s):
- 2155232
- PAR ID:
- 10686447
- Publisher / Repository:
- AIP Publishing
- Date Published:
- Journal Name:
- Chinese Journal of Chemical Physics
- Volume:
- 37
- Issue:
- 6
- ISSN:
- 1674-0068
- Page Range / eLocation ID:
- 857 to 862
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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