Theoretical study of the electronic spectra of uracil and thymine

A theoretical study of the electronic spectra of uracil and thymine using the complete active space SCF method combined with multi-configurational second-order perturbation theory find that the computed excitation energies have errors which are less than 0.3 eV. Research enabled the prediction of the presence of four pi to pi* singlet excited states with transition energies of less than 7.0 eV. Considering the solvent shifts, the calculated transition energies are in agreement with measured energies.