The unimolecular dissociation of HCO. V. Mixings between resonance states

Abstract

Articles you may be interested inVibrationally quantum-state-specific dynamics of the reactions of CN radicals with organic molecules in solution

Elementary reactions of formyl (HCO) radical studied by laser photolysis—transient absorption spectroscopy

“…All four profiles obtained were simultaneously fitted by a numerical solution of a system of differential equations corresponding to the reaction mechanism. The reaction mechanism used in the fits includes reactions (1-3) and additional reactions (7)(8)(9)(10)(11):…”

“…The only one possibility for an interfering process to lead to a decrease of the apparent rate constant is in reactions leading to the reproduction of formyl radicals (such as reactions (8b) and (9b)). Very little is known about these channels of reactions (8) and (9). To check out such a possibility, the experiments with the photolysis of acetaldehyde at 193 nm (where it has a ''hot'' absorption) were designed to evaluate the role of the secondary reaction of methyl radicals and hydrogen atoms with the precursor molecule.…”

“…Due to relatively weak C-H bond and large vibrational frequencies, the radical has isolated resonances at energies above the dissociation threshold. These resonances have been extensively studied both using spectroscopic techniques and theoretically [4][5][6][7][8][9]. This feature is expected to have a significant impact on the pressure fall-off curve for reaction (1) [10].…”

Influence of Vibrational Resonances and Coriolis Coupling on Dissociation Rates in the Near-threshold Unimolecular Fragmentation of HOCl

“…Anharmonic resonances induced by variations of J and/or K are common effects in small molecules. They have been also observed for HCO and HNO [36,37]. For these two molecules, however, the resonance widths are considerably larger Ϫ and therefore less sensitive with respect to slight changes of the level structure Ϫ than for state (6,0,0) of HOCl and the mean spacing between the levels is comparatively large.…”

Quantum Dynamics of Gas‐Phase SN2 Reactions

“…The latter are due to interactions between different states. For the HCO radical, Schinke and coworkers [126] found that rotational motion can influence the resonance widths in so far as a fine tuning with respect to energy is achieved via distinct rotational constants in different vibrational states. A similar scheme applies here, where, however, the fine tuning results from differences in the intermolecular wavenumber for the different progressions.…”