Electronic absorption spectra of cation radicals as a source of information regarding their conformations

On the basis of differences in the energy gaps between the molecular orbitals of the type of biphenyl, 2,2-dithienyl, 2-phenyl(thienyl)pyrrole, 2-phenylselenophene (photoelectronic spectroscopy), and their cation radicals (nanosecond laser spectroscopy) it was shown that ionization causes transition to a more planar molecular conformation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1213–1216, September, 1989.