Thermochemical data from gas-phase adsorption and methods of their estimation

Abstract

Nowadays, gas-phase chromatography represents one of the fastest and most efficient techniques for the investigation of chemical properties of superheavy elements. The classical gas-adsorption chromatography experiment with transactinide species performed in an isothermal regime or in a temperature gradient, at ambient gas pressures, or under vacuum conditions delivers observables for single atomic species that are dependent on the parameters of the experiment. In Part I of this chapter we present several methods to derive thermodynamic data of the investigated species from these observables, which are not dependent on the experimental parameters and which are therefore intercomparable. A reversal of these methods suggests the behavior of transactinide species based on predicted thermochemical data, which is instrumental for the design of experiments. In Part II of this chapter we demonstrate several methods for the prediction of thermochemical properties of the heaviest elements based on chemical trends established in the Periodic Table. This provides data limits complementary to results of modern relativistic calculations. Finally, only the direct comparison of predicted data to experimental results allows for conclusions to be made on trends of chemical properties among transactinides and their corresponding homologs and for further improvement of the mostly empirical prediction models suggested here.