THE SULFUR $K_\beta$ X-RAY EMISSION SPECTRA OF THIOPHENE AND SOME OF ITS SUBSTITUTED DERIVATIVES

Abstract

The sulfur $K_\beta$ X-ray photon emission spectra were obtained for thiophene and several of its 2- and 2,5-substituted derivatives using a vertically oriented double crystal X-ray $spectrometer.^{1}$ The spectra exhibit $variations^{2}$ which can qualitatively be interpreted on a molecular orbital basis. These variations are observed upon substitution of such entities as -COOH, C1, and Br for the hydrogens at the 2 and 5 positions The variations are attributed to inductive and resonance effects felt by the sulfur 3p orbitals participating in the sigma and pi bonding system of the aromatic thiophene skeleton.