An ab initio MO study on the thymine dimer and its radical cation

Misako Aida, Motohisa Kaneko, Michel Dupuis

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Ab initio SCF calculations with the 6-31G basis set for the thymine dimer (cys-syn form) and the thymine dimer radical cation are reported. The fusion of the thymine bases at the C5 and C6 positions involves the formation of a cyclobutane ring with puckering. The puckering causes a notable difference in the electronic structures of the two bases of the thymine dimer. The density of the HOMO orbital of the thymine dimer is localized on the O2, N1, and C6 atoms of both thymine rings, with the higher density on one of the rings. The HOMO orbital has a bonding character on the C6-C6 bond. In the thymine dimer radical cation, the unpaired electron is localized mainly on the lengthened C6-C6 bond with the higher density on one of the C6 atoms and to a lesser extent on the N1 atoms of both rings.

Original languageEnglish
Pages (from-to)949-957
Number of pages9
JournalInternational Journal of Quantum Chemistry
Issue number5
Publication statusPublished - Mar 5 1996


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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