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

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