Theoretical Calculation of the Deposition Temperature in Thermochromatography from the Thermodynamic Data

Abstract

A model was suggested for calculating the enthalpy of adsorption or deposition temperature in thermochromatography of ultramicroamounts of substances from the thermodynamic data. In this model, the entropy of adsorption on an inert surface is assumed to be the same as in the adsorption of adsorbate molecules on the surface of a macroamount of the same substance, and the enthalpy of adsorption, calculated with this assumption, shows good and universal correlation with the enthalpy of desublimation of a macroamount of the same substance. The process accompanied by chemical reactions on the surface is also described within the framework of this approach. The experimental data on thermochromatography of Zr, Hf, W, Re, Tl, Pb, Bi (carrier-free), and other analogs of transactinide elements under various conditions are in good agreement with the calculation results. Thus, the suggested model is applicable to interpretation and prediction of the thermochromatographic data.