A suitable design of a three-layer antireflection coating based on ZnSe and PbF2 layers on KCl windows for CO2 laser radiation is chosen to match the requirements for a low loss and moisture-protection coating. It is deposited on KCl plates by conventional and low-energy ion-assisted thermal evaporation. The local absorptance at different places both at the interfaces and in the volume of the layers is measured by the photothermal deflection technique at 10.6 mu m. A considerable decrease of the local absorptance is observed in the coating deposited by thermal evaporation with Ar-ion bombardment of energy 40 eV. Conclusions regarding the absorptance value distribution in the depth of the coating are drawn.