Considering vibrations in the thermodynamic functions of a solid adsorbate in slit-like pores

Problems that arise in refining calculations of the equilibrium thermodynamic functions of an adsorbate located near an adsorbent’s surface or inside slit-like pores when its collective vibrational motions are considered are discussed. A technique is proposed for calculating collective vibrations for a small number of vacancies in a defective heterogeneous adsorbate from changes in the number of degrees of freedom and the local frequencies in the frequency distribution function in an ideal bulk crystal.