Electrical properties of nucleic acid bases

The dipole polarizabilities for the five nucleic acid bases, uracil, cytosine, thymine, guanine, and adenine have been determined by the coupled perturbed Hartree-Fock (CPHF) method using a polarized double-zeta basis set. Electronic correlation corrections from second-order Møller-Plesset (MP2) perturbation theory are given. The treatment required to obtain accurate polarizabilities of these π systems was estimated from calculations on imidazole, benzene, and pyridine, giving results that are in good agreement with experiment. Similarly, optimal basis sets for static electrical properties were determined and applied to calculations of the dipole moments of the bases. With correlation corrections, these agree with experiment within 5% for all molecules except adenine.