The influence of frequency on the efficiency of dissociation of freons by microwave discharges

We have performed calculations of the efficiency of dissociation by the microwave induced discharges at low pressures. Monte Carlo simulation of electron transport under the influence of high frequency electric field and collisions with gas molecules was used to determine the dissociation efficiency in microwave discharges in freons which have been proposed as a technique for reducing the depletion of the ozone layer by freons initiated chemical reactions with ozone in the upper atmosphere. It was found that the modulation of the mean energy and the electron energy distribution function becomes smaller at very high frequencies (1 GHz) leading to significant reduction of the dissociation rate. Above 3 GHz electrons cannot follow the field changes and gain energy efficiently. Thus operation at higher electric field values or E/N is required to achieve significant dissociation in the GHz frequency range.