Vacuum ultraviolet emissions of trifluoromethane following electron impact in the wavelength range 50–130 nm

The dissociative excitation of CF3H by electron impact has been studied under single collision conditions for incident energies up to 600 eV. The emission spectrum in the wavelength range 50–130 nm shows many features arising from neutral and singly ionized fluorine and carbon fragments, as well as from neutral hydrogen atoms. Absolute cross sections for the observed features were measured at 200 eV incident energy, while the excitation functions of the most intense emissions were studied over the whole energy range. The threshold excitation of the hydrogen Lyman α line displays onsets at 18.4 and 34.0 eV, while that of the fluorine F I 95.5 nm feature shows only one onset at 33.0 eV. Possible dissociation channels are discussed.