Compared performances of the molecular orbital and density functional theories for fragments of biomolecules

As a preliminary to quantum-mechanical studies of nucleic acids, the possibilities of the molecular orbital (MO) method at the MP2 level and of the density functional theory (DFT) have been examined for typical fragments of nucleosides: methanol, tetrahydrofuran, 3-hydroxytetrahydrofuran and uracil. The results obtained from both methods using polarized split-valence basis sets are found to be consistent with each other, except for small but significant differences that are possibly related to the neglect of DFT self-interaction corrections.