AM1 and INDO/S calculations on electronic singlet and triplet states involved in excited-state intramolecular proton transfer of 3-hydroxyflavone

摘要

Energies and geometries of the electronic ground states and vertical transition energies and oscillator strengths of singlet-singlet and triplet-triplet transitions have been calcd for both tautomer forms of 3-hydroxyflavone. The resulting energy level diagram and calcd. excited-state spectra yield a consistent interpretation of the data from transient absorption measurements. It is concluded that all long-lived transient absorptions are due to triplet species and that an intrinsic barrier to proton transfer exists in the lowest triplet state.