X-RAY-EMISSION SPECTROSCOPY MEASUREMENTS OF FLUORINE-SUBSTITUTED METHANES

We present the carbon and fluorine x-ray emission spectra of methane a nd the fluoromethanes (CH4-xFx, x = 0, 1, 2, 3 and 4), measured in hig h resolution. Relative x-ray emission intensities in dipole velocity a nd length gauges have been derived from the independent particle appro ximation using Hartree Fock ground state molecular orbitals. The resul ts of the calculations are compared with the experimental spectra. In the experimental carbon (K-V) emission spectrum of CF4 We observe dipo le-forbidden electronic transitions. We suggest that these transitions arise due to vibronic coupling, i.e. intensity is borrowed from the d ipole-allowed transitions.