Three-state conical intersections in nucleic acid bases.

Spiridoula Matsika

doi:10.1021/jp0513622

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Three-state conical intersections in nucleic acid bases.

Spiridoula Matsika

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Abstract

The involvement of three-state conical intersections in the photophysics and radiationless decay processes of the nucleobases has been investigated using multireference configuration interaction methods. Three-state conical intersections have been located for the pyrimidine base, uracil, and the purine base, adenine. In uracil, a three-state degeneracy between the S(0), S(1), and S(2) states has been located at 6.2 eV above the ground-state minimum energy. This energy is 0.4 eV higher than vertical excitation to S(2) and at least 1.3 eV higher than the two-state conical intersections found previously. In adenine, two different three-state degeneracies between the S(1), S(2), and S(3) states have been located at energies close to the vertical excitation energies. The energetics of these three-state conical intersections suggest they can play a role in a radiationless decay pathway present in adenine. The existence of two different seams of three-state conical intersections indicates that these features are common and complicate the potential energy surfaces of adenine and possibly many other aromatic molecules.

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Adenine Models, Chemical Molecular Structure Nucleic Acids Uracil Journal Article Research Support, U.S. Gov't, Non-P.H.S.

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Spiridoula Matsika. 2005-08-25. Three-state conical intersections in nucleic acid bases.. https://doi.org/10.1021/jp0513622

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