Electrophysical and kinetic characteristics Of Cl-2/Ar plasma were investigated to understand the influence of the addition. of Ar on the volume densities and fluxes of active particles, both neutral and charged. Our analysis combined both,experimental methods and plasma modeling. It was found that addition of Ar to Cl-2 leads to deformation of the electron energy distribution function and an increase of the electron mean energy due to the "transparency" effect. Direct electron impact dissociation Of Cl-2 molecules represents the main source of chlorine atoms in the plasma volume. The contributions of stepwise dissociation and ionization involving Ar metastable atoms were found to be negligible. Addition of Ar to Cl-2 causes the decrease of both electron and ion densities due to a decrease in the total ionization rate and the acceleration of heterogeneous decay of charged particles. (C) 2003 American Vacuum Society.