Molecular orbital interpretation of the ultra-violet absorption spectra of unconjugated aliphatic nitramines

A VE.SCF.CI. calculation of the excited states of nitramide, N-methyl nitramine, and N,N-dimethyl nitramine has been carried out. The assignments for the latter two have been extended to other unconjugated, primary and secondary aliphatic nitramines. All valence electrons, i.e., σ-, π- and text-decoration:overlineπ-electrons, except for the oxygen atom 2s lone pairs, were included in the calculation. The necessity of including electrons occupying sigma bonds adjacent to the “chromophore” has been illustrated.