HeI photoelectron spectra of o-nitro acetanilide derivatives have been investigated systematically on a double-chambers UPS machine-Ⅱ which was especially designed for the study of transient species. The assignment of the spectra are also done using the optimized MNDO molecular orbital calculation for each molecules studied. It is shown that the difficulty of synthesis polymer from these o-nitro acetanilide derivatives depends on their lowest experimental ionization potential (IP).

Key words: QUANTUM CHEMISTRY, NITROBENZENE P, ELECTRONIC STRUCTURE, ACETANILIDE P