An investigation of the electronic structure of α, β-unsaturated acetylamino acid ethyl esters using He(I) and He(II) photoelectron spectroscopy

The He(I)- and He(II)-excited photoelectron spectra of the ethyl esters of α, β-unsaturated acetylamino acids (1a–4a) are presented and discussed. The spectra are assigned by comparison with those of related molecules and by analysis of the relative band intensities under different radiation sources. The effects of β-substitution on the electronic structure and conformation are also discussed.