The chemistry of the superheavy elements. I. Pseudopotentials for 111 and 112 and relativistic coupled cluster calculations for (112)H+, (112)F2, and (112)F4

Abstract

One- and two-component (spin–orbit coupled) relativistic and nonrelativistic energy adjusted pseudopotentials and basis sets for the elements 111 and 112 are presented. Calculations on the positively charged monohydride of the recently discovered superheavy element 112 are reported. Electron correlation is treated at the multireference configuration interaction and coupled cluster level and fine structure effects are derived from a single-reference configuration interaction treatment. Relativistic effects decrease the (112)H+ bond distance by 0.41 Å. This bond contraction is similar to the one calculated recently for (111)H [Chem. Phys. Lett. 250, 461 (1996)]. As a result the bond distance of (112)H+ (1.52 Å) is predicted to be smaller compared to those of the hydrides of the lighter congeners HgH+ (1.59 Å), CdH+ (1.60 Å) and similar to that of ZnH+ (1.52 Å). We predict that (112)H+ is the most stable hydride in the Group 12 series due to relativistic effects. As in the case of (111)H the relativistic increase of the stretching force constant is quite large, from 1.5 to 4.3 mdyn/Å at the coupled cluster level. The trend in the dipole polarizabilities of the Group 12 elements is discussed. Relativistic and electron correlation effects are nonadditive and due to the relativistic ns contraction (n=7 for 112), correlation effects out of the (n−1)d core are more important at the relativistic than the nonrelativistic level. We also show evidence that element 112 behaves like a typical transition element, and as a consequence the high oxida-tion state +4 in element 112 might be accessible.