Theoretical investigations of the proton transfer reaction in the hydrogen-bonded complex of 2-pyrimidinone with water

Andrej L. Sobolewski, Ludwik Adamowicz

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The potential energy (PE) functions of the electronic ground and lowest ππ* excited singlet states of the hydrogen-bonded cyclic complex of 2-pyrimidinone with water were theoretically investigated along the proton transfer (PT) reaction coordinate. The full geometry optimization was performed along the PT reaction path. In the geometry optimization the Hartree-Fock method and the configuration interaction method with single excitations (CIS) were used. The energy calculations at the optimized geometries were performed with the complete-active-space self-consistent-field (CASSCF) method and with the second-order perturbation theory, employing the CASSCF wave function as the reference. For the ground state, calculations were also performed with the Moller-Plesset second-order perturbation theory (MP2). We found that the hydroxy form of the 2-pyrimidinone:water complex is stable in the ground electronic state while the hydroxy-to-oxo transformation reaction of the complex is by about 0.67 eV exothermic on the lowest 1 ππ* excited state PE surface. However, there is a barrier of about 0.19 eV along the PT reaction path on this surface. The top of the barrier is below the energy of the vertical excitation So1ππ*; thus, the photoexcited system has sufficient excess energy for the PT reaction to occur spontaneously.

Original languageEnglish (US)
Pages (from-to)14277-14284
Number of pages8
JournalJournal of Physical Chemistry
Volume99
Issue number39
StatePublished - Jan 1 1995
Externally publishedYes

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Pyrimidinones
Proton transfer
Hydrogen
protons
Water
hydrogen
Excited states
water
Geometry
excitation
Potential energy functions
self consistent fields
Potential energy surfaces
perturbation theory
geometry
potential energy
Electronic states
Wave functions
Commonwealth of Independent States
optimization

ASJC Scopus subject areas

  • Engineering(all)
  • Physical and Theoretical Chemistry

Cite this

Theoretical investigations of the proton transfer reaction in the hydrogen-bonded complex of 2-pyrimidinone with water. / Sobolewski, Andrej L.; Adamowicz, Ludwik.

In: Journal of Physical Chemistry, Vol. 99, No. 39, 01.01.1995, p. 14277-14284.

Research output: Contribution to journalArticle

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