Calculation of <i>n</i>→II Transition Energies in N-Heterocyclic Molecules by a One-Electron Approximation
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- Lionel Goodman
- Department of Chemistry, Florida State University, Tallahassee, Florida
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- Robert W. Harrell
- Department of Chemistry, Florida State University, Tallahassee, Florida
書誌事項
- 公開日
- 1959-05-01
- DOI
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- 10.1063/1.1730147
- 公開者
- AIP Publishing
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説明
<jats:p>The one-electron LCAO-MO formalism is applied to n→π* transition energies in N-heterocyclic molecules. |βnπspec| is shown to be ∼1 ev smaller than |1βππspec| for (n, π*) states possessing no nodes through nitrogen atoms. Reasonable values are 1βnπspec≈—2.3 ev, 3βnspec≈—2.0 ev. Calculations of transition energies, both singlet-singlet and singlet-triplet, are made for 16 molecules, yielding semiquantitative agreement with experiment. Prediction of the assignment of the lowest excited singlet and triplet levels is made for a number of cases. The singlet-triplet split in the lowest (n, π*) configuration is predicted to undergo a strong orientation dependence in the 6-membered azines. Substitution effects are considered and orientation effects on the n→π* blue shift upon conjugative substitution are treated. (n, π*) states with nodes through nitrogen atoms are discussed qualitatively.</jats:p>
収録刊行物
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- The Journal of Chemical Physics
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The Journal of Chemical Physics 30 (5), 1131-1138, 1959-05-01
AIP Publishing