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The intensity of the shake-up satellites present in the solid-phase XPS spectra of paranitroaniline ( 1 ), 2-amino-5-nitropyridine ( 2 ) and 2-amino-5-nitropyrimidine ( 3 ) decreases from ( 1 ) to ( 3 ) in agreement with CNDO/S CI calculations. The HOMO—LUMO energy gap appears to be responsible for the observed trend.

The UV photoelectron spectrum of [2,2] metacyclo-2,6-pyridinophane has been analyzed on the basis of a perturbational molecular orbital analysis and CNDO/2 calculations. Through space and through bond interactions are shown to be present between the two pyridine rings. In particular a strong interaction has been found between the nitrogen lone pairs and the π systems of the rings.

The electron transmission spectra of 4H-thiopyran-4-one. 4H-pyran-4-thione and 4H-thiopyran-4-thione have been recorded in the 0–6 eV energy range and the observed resonances assigned to the corresponding anion states. Unlike γ-pyrone, its sulphur derivatives possess low-energy Σ anion states.