Calculation of the adsorption interaction of argon and krypton on the relaxed (100) faces of sodium chloride and potassium chloride

Abstract

The adsorption energy has been calculated for isolated Ar and Kr atoms on relaxed (100) faces of NaCl and KCl. Relaxation of the surface layers increases the adsorption energy over the cation position by about 30 % for the gases on NaCl and about 7 % on KCl. The effect is much smaller for other positions on the surface. The choice of the ion-inert gas potential function is discussed and the expressions for the electrostatic field interaction due to the relaxed layers are presented. The results are shown on adsorption potential contour maps and analysed using the hindered translation model. Values of the isosteric heat and the theoretical heat capacity curves are derived, together with an estimate of the Henry's law constants at 77.5 K.