CHED 1387

The electronic states involved in the UV-induced excitation of adenine from its vibrational ground state models the complex photochemistry involved in DNA nucleic bases.  Identifying and characterizing these states is necessary for understanding the relaxation pathway, whose timescale governs possible mutagenic dimer formation. Various theoretical electronic structure methods were used to characterize the excited states of adenine, including the expansion of basis sets for the accurate description of diffuse electronic behavior. Comparing the ordering of the electronic states at the Franck-Condon point using a broad range of basis sets also clarifies the role of  π-σ* and π-π* states in excitation and relaxation. With these techniques, we hope to identify which states are involved in the excitation and relaxation of adenine and suggest a dynamic decay mechanism from the ordered excited states.