Knowledge Bank

The vacuum ultraviolet spectra of ethylene and several substituted ethylenes will be presented. The substituent groups considered are those which are thought to exert a direct influence on the $\pi$ bond either through an inductive or overlapping effect. Among the groups considered are alkyl and halogen substituents. The comparison of the relative effects of the various substituents on the first intense band, which occurs in the region between 1500$\backslash AA$ and 2000$\backslash AA$, will be discussed. Additional aspects of this and other electronic transitions will be considered from the stand point of each substituted ethylene being a perturbed form of the parent molecule ethylene. Various theoretical models of ethylene will be utilized in the considerations of the several systems.