Abstract
Simplified representations of branching fractions for thermal unimolecular two-channel reactions are discussed. The dissociation of formaldehyde serves as an illustrative example. Quantum-corrected classical trajectory calculations on an ab initio potential energy surface are combined with master equation calculations for collisional energy transfer. The treatment accounts for roaming atom dynamics. The dependence of the channel branching fractions on the bath gas pressure and temperature, on the collision efficiencies, and on the difference of channel threshold energies, are explored. It is discussed to what extent the derived simplified representations of channel branching fractions can be generalized.
Dedicated to: Friedrich Temps at the occasion of his 65th birthday.
Acknowledgement
This work is dedicated to Professor Friedrich Temps at the occasion of his 65th birthday. It acknowledges many years of inspiring interaction. Help by E. Tellbach and financial support of this project by the Deutsche Forschungsgemeinschaft (Funder Id: http://dx.doi.org/10.13039/501100001659, Project TR69/20-3) are also gratefully acknowledged. The work was performed in accordance with the state task of the Ministry of Science and Higher Education RF (to UVG), state registration No. 0089-2019-0002.
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