Is E112 a relatively inert element? Benchmark relativistic correlation study of spectroscopic constants in E112H and its cation.

We report the first results of relativistic correlation calculation of the spectroscopic properties for the ground state of E112H and its cation in which spin-orbit interaction is taken into account non-perturbatively. Studying the properties of E112 (eka-Hg) is required for chemical identification of its long-lived isotope, (283)112. It is shown that appropriate accounting for spin-orbit effects leads to dramatic impact on the properties of E112H whereas they are not so important for E112H(+). The calculated equilibrium distance, R(e) (calc)=1.662 Angstrom, in E112H is notably smaller than R(e) (expt)=(1.738+/-0.003) Angstrom and R(e) (calc)=1.738 Angstrom in HgH, whereas the dissociation energy, D(e) (calc)=0.42 eV, in E112H is close to D(e) (expt)=0.46 eV and D(e) (calc)=0.41 eV in HgH. These data are quite different from R(e) (NH)=1.829 Angstrom and D(e) (NH)=0.06 eV obtained for E112H within the scalar-relativistic Douglas-Kroll approximation. Our results indicate that E112 should not be expected to behave like a noble gas in contrast to the results by other authors.