Electronic structure aspects of the spin-forbidden reaction CH{sub 3}(X{sup 2}A{sub 2}{sup {double_prime}})+N({sup 4}S){r_arrow}HCN(X{sup 1}{Sigma}{sup +})+H{sub 2}(X{sup 1}{Sigma}{sub g}{sup +})

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.474862· OSTI ID:542173

Sadygov, R G; Yarkony, D R ^[1]

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1. Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)

Second order configuration interaction wave functions based on molecular orbitals determined from a state-averaged multiconfigurational self-consistent field procedure are used to investigate the intermediate complex driven model for the spin-forbidden reaction CH{sub 3}(X{sup 2}A{sub 2}{sup {double_prime}})+N({sup 4}S){r_arrow}HCN(X{sup 1}{Sigma}{sup +})+H{sub 2}(X{sup 1}{Sigma}{sup +}). The minimum energy crossing point (MECP), the minimum energy point on the surface of intersection connecting the reactant channel, {sup 3}A{sup {prime}{prime}} potential energy surface, and product channel {sup 1}A{sup {prime}} potential energy surface, is determined directly, i.e., without {ital a priori} characterization of the individual potential energy surfaces. The MECP is found to be 8.2 kcal/mol below of the reactants. The structure at the MECP clearly evinces the incipient formation of a H{sub 2} bond. Barrierless paths from the reactants to the intermediate complex-methylnitrene, from the intermediate complex to the MECP, and from the MECP to the products are established. The absence of a barrier on these paths supports the intermediate complex mechanism. Spin{endash}orbit interactions are determined to be {approximately}30cm{sup {minus}1} for points on the surface of intersection in the vicinity of the MECP. Spin{endash}orbit interactions and the local potential surface topology at the MECP are used to probe the efficiency of the intersystem crossing using the Landau{endash}Zener model. A reduced dimensionality model is proposed. {copyright} {ital 1997 American Institute of Physics.}

• DOE Contract Number: FG02-91ER14189
• OSTI ID: 542173
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 13 Vol. 107; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ATMOSPHERIC CHEMISTRY
CHEMICAL REACTIONS
COMBUSTION KINETICS
CONFIGURATION INTERACTION
ELECTRONIC STRUCTURE
L-S COUPLING
METHYL RADICALS
NITROGEN
ORGANIC COMPOUNDS
PLANETARY ATMOSPHERES
REACTION KINETICS
SELF-CONSISTENT FIELD