title: Electronic structures of cephalosporin and penicillin moieties.
mesh_terms: D002511:Cephalosporins; D004583:Electrons; D004735:Energy Transfer; D010406:Penicillins; D011789:Quantum Theory; D013057:Spectrum Analysis
chemical_list: D002511:Cephalosporins; D010406:Penicillins