Intermetallic Compounds of Element 112: the Electronic Structure and Bonding

The next heaviest element which is to be studied chemically at the JINR, Dubna, [1] and GSI [2] is element 112. Its properties are expected to be unique: high volatility and inertness due to the very strong relativistic stabilization of the 7s electrons and the closed-shell configuration, 7s6d [3]. The surface of the chromatography column in the gas-phase chromatography experiments is to be made out of gold and palladium, since the interaction of Hg, the nearest homolog of element 112, with those metals was found to be rather strong [4]. To detect element 112 on those surfaces, the knowledge of its adsorption enthalpy is highly desirable. As a first step in the study of the metal-surface interaction, we have calculated here the electronic structure and bonding of the dimers, HgX and 112X (X = Pd, Ag and Au). The calculations were performed using the fully relativistic density-functional method (DFT) with the relativistic general gradient approximation (RGGA) for the exchange-correlation potential [5]. The Mulliken population analysis was applied additionally to study bonding in these systems. The calculated RGGA binding energies, De, optimized bond lengths, Re, and harmonic frequencies, w, are shown in Table 1. The obtained De are probably too large by about 0.2 eV, which is an average error of the DFT method [5].