The HeI photoelectron spectroscopy of compounds 1, 4-Naphthoquione, tetracyano-benzoguione, di-o-phathalic anhyclrid acid have been studied for the first time. To assign these spectra, RHF/3-21G optimization and RHF/STO-6G molecular orbital calculation for these three compounds have also been performed. The results show that: the first ionization peak of these compounds are all related to the π bonds of the benzene ring and carbonyl, and the increase of the ionization potentials of HOMO is linear with the gradual addition of the carbonyl in the HOMO. The second peak and the third peak of the three compounds are all related to the lone pair ionization of atom O. From these, we can conclude that: the carbonyl is the characteristics group of this kind of compound. Furthermore we also find that: the higher symmetry the compound has, the greater the average of n^-/n^+ is, and the greater n^-, n^+ spitting it has too.

Key words: CARBONYL COMPOUNDS, QUINONE, ACID ANHYDRIDE