Theoretical predictions of properties and adsorption behaviour of group 1 and 2 elements, including elements 119 and 120, on hydroxylated quartz surfaces from periodic DFT calculations

Abstract

Adsorption properties of group 1 and 2 elements Cs, Fr and E119 and Ba, Sr and E120, respectively, and of group 1 hydrides and hydroxides on hydroxylated quartz surfaces were calculated using a periodic relativistic DFT approach. The results show that all the considered group 1 and 2 elements should adsorb rather moderately on the quartz surfaces, with E119 and E120 most weakly, due to the strong relativistic stabilisation and contraction of the 8s atomic orbital. This means that E119 and E120 should have a deposition peak in the quartz chromatography column with a temperature gradient from room temperature to far below zero in the sequence Cs/Ba > Fr/Ra > E119/E120. For group 1 element MH and MOH, the adsorption energies are high, so that the adsorption–desorption equilibrium should be reached at very high temperatures, with the following trend in the adsorption strength MH > MOH >> M. Relativistic periodic DFT calculations of the adsorption properties of group 1 and 2 elements, including elements 119 and 120, and of their hydrides and hydroxides, on the hydroxylated quartz surfaces.