Evidence of Effective Potential Barriers in the X-Ray Absorption Spectra of Molecules

We interpret the enhanced lines and frequent failure to detect Rydberg structure in the x-ray absorption spectra of molecules in terms of ``inner-well'' and ``outer-well'' states which result from an effective potential barrier located near the electronegative atoms in the molecule. The K and LII, III spectra of sulfur in SF6 are discussed in detail and all prominent features are identified. X-ray absorption spectra of molecules in which a B, S,...