title: An extended semi-empirical molecular orbital study of the pi pi excited states of nucleic acid bases.
mesh_terms: D000225:Adenine; D003596:Cytosine; D006147:Guanine; D009690:Nucleic Acid Conformation; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014498:Uracil; D014618:Vacuum
chemical_list: D014498:Uracil; D006147:Guanine; D003596:Cytosine; D000225:Adenine