Absolute Electron Attachment Cross Sections Research Articles

Electron attachment to hexafluoropropylene oxide (HFPO).

We probe the electron attachment in hexafluoropropylene oxide (HFPO), C3F6O, a gas widely used in plasma technologies. We determine the absolute electron attachment cross section using two completely different experimental approaches: (i) a crossed-beam experiment at single collision conditions (local pressures of 5 × 10-4 mbar) and (ii) a pulsed Townsend experiment at pressures of 20-100 mbar. In the latter method, the cross sections are unfolded from the electron attachment rate coefficients. The cross sections derived independently by the two methods are in very good agreement. We additionally discuss the dissociative electron attachment fragmentation patterns and their role in the radical production in industrial HFPO plasmas.

Swarm-determined electron attachment cross sections as a function of electron energy

An unfolding procedure is described whereby the known electron energy distribution function in the swarm F(( epsilon ), epsilon ) at each mean electron energy ( epsilon ) is used as the 'smearing out' function to unfold the monoenergetic attachment rate M( epsilon ) from the experimentally determined electron attachment rate functions Rexp(( epsilon )). From the monoenergetic attachment rate the absolute electron attachment cross section as a function of electron energy epsilon is calculated. The cross section functions determined from the unfolding of swarm data for a number of molecules compare well with those obtained using quasi-monoenergetic electron beams. This successful unfolding of swarm data enhances the potential of the electron swarm method in electron attachment studies.