TY - JOUR
T1 - Nature of the change in the rotational barrier of the methyl group due to S0→S1 excitation
AU - Nakai, H.
AU - Kawai, M.
N1 - Funding Information:
The authors thank Prof. M. Fujii for valuable discussion. The calculations were performed at the Computer Center of the Institute for Molecular Science and at the Media Network Center (MNC) of Waseda University. Part of this study was supported by a Grant-in-Aid for Scientific Research from the Japanese Ministry of Education, Science, and Culture, and by a Waseda University Grant for Special Research Projects.
PY - 1999/7/2
Y1 - 1999/7/2
N2 - Internal rotation of the methyl group in o- and m-fluorotoluenes has been investigated by the ab initio molecular orbital method. The calculated rotational barriers in the S0 and S1 states are in reasonable agreement with experimental values. Steric and electrostatic effects are not important for the changes in the rotational barriers. An electronic effect is found to be the most significant. Especially, the rotational barriers in the S1 states are determined by the stability of the LUMOs, which involves a new type of hyperconjugation between the ortho-carbon and the hydrogens of the methyl group.
AB - Internal rotation of the methyl group in o- and m-fluorotoluenes has been investigated by the ab initio molecular orbital method. The calculated rotational barriers in the S0 and S1 states are in reasonable agreement with experimental values. Steric and electrostatic effects are not important for the changes in the rotational barriers. An electronic effect is found to be the most significant. Especially, the rotational barriers in the S1 states are determined by the stability of the LUMOs, which involves a new type of hyperconjugation between the ortho-carbon and the hydrogens of the methyl group.
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U2 - 10.1016/S0009-2614(99)00517-5
DO - 10.1016/S0009-2614(99)00517-5
M3 - Article
AN - SCOPUS:0000291505
SN - 0009-2614
VL - 307
SP - 272
EP - 276
JO - Chemical Physics Letters
JF - Chemical Physics Letters
IS - 3-4
ER -