Fine structure above the carbon K-edge in methane and in the fluoromethanes

Synchroton radiation has been utilized to obtain high resolution soft X-ray absorption spectra above the carbon K-edges in CH 4 , CD 4 and the fluoromethanes. The results near threshold are in close agreement with forward scattering electron energy loss data in the cases where that comparison can be made. With increasing fluorination the Rydberg-like threshold spectra of methane shift to higher energy and evolve into a complex band in CF 4 . Well above threshold extended fine structure (EXAFS) is observed in CF 4 .