Abstract
A semiempirical VESC-FMO-CI calculation was performed with the purpose of making a systematic survey on the π-π* electronic transitions of pteridine and its all possible amino-derivatives. The calculated data, particularly those for the singlet π-π* transition energies, were in good agreement with the observed data on both of the mono-and poly-substituted derivatives. Also, the effects of amino-substitution upon the polarization directions and upon the changes of the electron densities in going from the ground state to the lowest 1 (π, π*) state were discussed.
