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Ab initio study on mechanisms of singlet oxygen reaction with ethylene
Author(s) -
Chen DeZhan,
Chen BaoJi,
Ning ShiGuang
Publication year - 1994
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19940120104
Subject(s) - chemistry , ab initio , ethylene , saddle point , singlet state , anharmonicity , dissociation (chemistry) , computational chemistry , eigenvalues and eigenvectors , ab initio quantum chemistry methods , molecular physics , atomic physics , excited state , molecule , quantum mechanics , organic chemistry , physics , geometry , catalysis , mathematics
The reaction of singlet oxygen with ethylene has been studied at the ab initio level with both HF/3–21G and HF/6–31G* basis sets, fully optimizing the geometries of the critical points. The transition state leading to the intermediate peroxirane from the initial reactants is found, located at 81.71 kJ/mol above the dissociation limit The vibrational analysis is done with two basis sets. From the results it can be seen that the frequencies have not been made an improvement obviously with augmented 6–31G* compared to 3–21G basis; it follows that main reason for too high HF/3–21G frequency could mainly be the vibrational anharmonicity. The eigenvector corresponding to the single imaginary vibrational frequency is dominated by the larger O—O distance. The finding of the transition state confirms that the peroxirane minimum can be reachable passing through a peroxirane‐like saddle point. In addition, the mechanisms of the reaction forming oxirane are discussed as well.