Abstract
The near ultraviolet absorption spectra of simple substituted benzenes in a vapor state show fine structure. These A1g→B2μ transitions (260 mμ absorption bands) are forbidden, so their absorption strengths are weak. Furthermore, the specificities between their structures, or substituents, and the corresponding spectra were not enough to permit a satisfactory analysis of mixtures. Heterocyclic, and aliphatic compounds showed only incomplete fine structure. It is theoretically considered that all ultraviolet absorption spectra show fine structure, and the exploitation of a useful analytical method is expected as the apparatus is so improved that a fine structure in far ultraviolet region is observed for many kinds of compounds.
