Morozov Alexander N, Medvedkov Iakov A, Azyazov Valeriy N, Mebel Alexander M
Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
Samara National Research University, Samara 443086, Russian Federation.
J Phys Chem A. 2021 May 13;125(18):3965-3977. doi: 10.1021/acs.jpca.1c01545. Epub 2021 Apr 30.
Quantum chemical calculations of the CHO potential energy surface (PES) were carried out to study the mechanism of the phenoxy + O(P) and phenyl + O reactions. CASPT2(15e,13o)/CBS//CASSCF(15e,13o)/DZP multireference calculations were utilized to map out the minimum energy path for the entrance channels of the phenoxy + O(P) reaction. Stationary points on the CHO PES were explored at the CCSD(T)-F12/cc-pVTZ-f12//B3LYP/6-311++G** level for the species with a single-reference character of the wave function and at the CASPT2(15e,13o)/CBS//B3LYP/6-311++G** level of theory for the species with a multireference character of the wave function. Conventional, variational, and variable reaction coordinate transition-state theories were employed in Rice-Ramsperger-Kassel-Marcus master equation calculations to assess temperature- and pressure-dependent phenomenological rate constants and product branching ratios. The main bimolecular product channels of the phenoxy + O(P) reaction are concluded to be -benzoquinone + H, 2,4-cyclopentadienone + HCO and, at high temperatures, also phenyl + O. The main bimolecular product channels of the phenyl + O reaction include 2,4-cyclopentadienone + HCO at lower temperatures and phenoxy + O(P) at higher temperatures. For both the phenoxy + O(P) and phenyl + O reactions, the collisional stabilization of peroxybenzene at low temperatures and high pressures competes with the bimolecular product channels.
