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Unimolecular dissociation of HOCl near threshold: Quantum state and time-resolved studies
被引:47
作者:
Barnes, RJ
[1
]
Dutton, G
[1
]
Sinha, A
[1
]
机构:
[1] UNIV CALIF SAN DIEGO,DEPT CHEM & BIOCHEM,LA JOLLA,CA 92093
关键词:
D O I:
10.1021/jp972668e
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
The unimolecular dissociation of HOCl has been examined by accessing several rotational resonances of the 6 nu(OH) vibrational level using overtone-overtone double resonance. An examination of the energetic thresholds for opening various OH fragment rotational states allows us to determine the dissociation energy for the Cl-O bond to be D-0 = 19 288.8 +/- 0.6 cm(-1) as well as confirm the absence of any appreciable barrier (less than or equal to 2 cm(-1)) along the reaction coordinate. Time-resolved measurements of the unimolecular dissociation rates arising from excitation to selected \J,K-a] quantum states of the 6 nu(OH) vibrational level are found to be substantially slower than that expected on the basis of RRKM theory, and as a function of energy, these rates exhibit recurrent maxima that approximately correlate with the rotational energy level spacings of the OH((2) Pi(3/2)) manifold. The OH fragment product state distributions resulting from near-threshold unimolecular dissociation are found to be hotter than those predicted by phase space theory.
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页码:8374 / 8377
页数:4
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