Predictions of adsorption behaviour of the heaviest elements in a comparative study from the electronic structure calculations

Abstract

Summary Thermodynamics of adsorption of gaseous species on the surface of a gas chromatography column is considered using the knowledge of the electronic structure of the adsorbate. Relevant equations based on a model of mobile adsorption are offered to predict the adsorption temperature, T ads, of a heavy-element (or its compound) with respect to T ads of its lighter homolog (or the same type of compound). A case of adsorption of OsO4 and HsO4 on an inert (quartz or silicon nitride) surface of a chromatography column is taken, as an example. The influence of various properties of the adsorbate, such as molecular weight and size, on T ads is analyzed to show that those factors should not be ignored in intentionally accurate predictions of T ads. A comparison of the desorption constants of OsO4 and HsO4 obtained with the use of the calculated spectroscopic properties shows that HsO4 should be significantly more volatile than OsO4, mainly due to the entropy factor.