Fully relativistic density-functional-theory calculations of the electronic structures of MO4 ( M=Ru , Os, and element 108, Hs) and prediction of physisorption

Fully relativistic, four-component density-functional-theory calculations were performed on MO₄ ( M=Ru , Os, and element 108, Hs). Implementation of the noncollinear spin-polarized approximation in the method and the usage of large optimized sets of numerical basis functions have resulted in a high accuracy of the calculated molecular properties, especially the molecular polarizabilities. The calculated properties were used to determine the adsorption energy of HsO₄ on inert surfaces using a physisorption model. The calculated -ΔH_ads(HsO₄)=45.4±1kJ/mol on quartz is in excellent agreement with the experimental value of 46±2kJ/mol . Our calculations indicate a reversal of the trend in the volatility of MO₄ (as desorption from the surface) in group 8, RuO₄<OsO₄>HsO₄ , a trend that is also observed experimentally. Although inclusion of relativistic effects is crucial for obtaining accurate energetics, the general trends in the properties (e.g., volatility) of the MO₄ compounds are already reproduced within a nonrelativistic treatment.