Electronic structure of 1,4-dihydro-1,2,4,5-tetrazines and of related 1,4-dihydroaromatic compounds. Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry, 10:1633--1637, 1985. [PUMA: MO MO;MO MO;hexazine azine;photoelectron configuration cyclic electron spectra tetrazine;cyclohexadiene tetrazine;pyrazine voltammetry]