X-Ray Photoelectron Spectroscopy of Chloromethanes and Chloroethanes

X-Ray photoelectron spectra of chloromethanes (CH4−nCln, n=2,3,4) and chloroethanes (CH3CH3−nCln, n=1,2,3) in vapor phase were observed employing Mg Kα radiation. The observed Cls binding energies were analyzed by means of Siegbahn’s electrostatic potential model and charge densities calculated by the CNDO/2 method, and the effects of inclusion and exclusion of Cl 3d atomic orbitals in the basis set of the CNDO/2 calculation is critically investigated. The assignment of all valence electron levels of above molecules were performed with the aids of the CNDO/2 calculations incorporated with Gelius’ intensity model and the reported data of ultraviolet photoelectron spectroscopy.