Theoretical investigations of the excited-state intramolecular proton transfer reaction in N-substituted-3-hydroxypyridinones

Andrzej L. Sobolewski, Ludwik Adamowicz

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Abstract

The potential energy functions of the electronic ground state, as well as the lowest nπ* and ππ* excited singlet states of 3-hydroxy-4-pyridinone and 3-hydroxy-2-methyl-4-pyridinone, have been theoretically investigated along the proton transfer (PT) reaction coordinate. The full geometry optimization has been performed along the PT reaction path. In the geometry optimization, the Hartree-Fock approximation and the configuration interaction scheme with single excitations have been employed. The energy calculations at the optimized geometries have been performed with the complete-active space self-consistent field (CASSCF) method followed by second-order perturbation theory calculations, employing the CASSCF wave function as the reference. We found that the near-degeneracy between the ππ* and nπ* excited singlet states, which is removed upon methyl substitution, might be the factor which differentiates the two systems with respect to the excited state intramolecular PT reaction. A simple vibrational model has been proposed for investigation of the dynamics of the process.

Original languageEnglish (US)
Pages (from-to)67-78
Number of pages12
JournalChemical Physics
Volume193
Issue number1-2
DOIs
StatePublished - Apr 1 1995

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ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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