Investigation of Potential Energy Surfaces of Reaction Systems Containing Ethylene, Hydrogen, and Oxygen Atoms by Quantum Chemical Calculations

• Published in: Russian journal of physical chemistry. B Vol. 17; no. 2; pp. 336 - 345
• Main Authors: Davtyan, A. H., Manukyan, Z. O., Arsentev, S. D., Tavadyan, L. A., Arutyunov, V. S.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.04.2023; Springer Nature B.V
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Decomposition reactions; Density functional theory; Enthalpy; Ethylene; Hydrogen; Hydrogen atoms; Isomerization; Kinetics and Mechanism of Chemical Reactions; Mathematical analysis; Oxidation; Oxygen atoms; Physical Chemistry; Potential energy; Quantum chemistry; Radicals; CBS-QB3; DFT methods; oxidation; B3LYP; ethylene; potential energy surface; Gaussian software package
• DOI: 10.1134/S1990793123020239
• ISSN: 1990-7931

In order to study the potential energy surfaces (PESs) of systems containing ethylene, hydrogen, and oxygen atoms, quantum chemical calculations are carried out using the hybrid B3LYP method of the density functional theory (DFT) and the composite CBS-QB3 method. An enthalpy diagram reflecting the PES of this reaction system is constructed. It is shown that the addition of a hydrogen atom to ethylene with the formation of an ethyl radical occurs through the formation of a van der Waals complex. The diagram of enthalpies of monomolecular reactions of decomposition and isomerization of the ethoxyl radical is presented in detail, and a conclusion is made about the probability of their occurrence. The global PES minimum of the system describing the sequential addition of hydrogen and oxygen atoms to ethylene is the hydroxyethyl radical. Intermediates CHCH 2 OH and CH 2 OCH 2 are localized on the PES of the C 2 H 4 + O system and possible pathways for their further transformation are analyzed. The data obtained make it possible to estimate the ranking of individual elementary reactions in the processes of combustion and oxidation of hydrocarbons and the probabilities of various directions for the transformation of chemical species in the studied systems.