| Abstrakt: |
Recently published scalar-relativistic energy-adjusted pseudopotentials have been employed, in valence ab-initio calculations using extended basis sets, for the determination of geometries, atomization energies and rotational barriers of the X2H6 (X = Si, Ge, Sn, Pb) compounds. While the importance of relativistic effects is not unexpected (the X-X bond length, r(XX), changes by -14 pm for X = Pb), the significant impact of core polarization for the heavy post-d elements (Δr(XX) = -5 pm for X = Pb) comes as a surprise. Comparison against all-electron calculations, including core-valence correlation, for Ge2H6 proves the frozen-core and core-polarization parts of our pseudopotential to be accurate to ∼ 2 and 1 pm, respectively, for r(XX). |
