Quasi-relativistic coupled cluster calculations of electric dipole moments and dipole polarizabilities of GeO, SnO, and PbO

Abstract

Electric dipole moments and static dipole polarizabilities of the series of oxides including a heavy atom, GeO, SnO, and PbO in their $^{1}$Σ ground states have been calculated by the Coupled Cluster CCSD(T) method. Scalar relativistic effects were considered by the Douglas-Kroll-Hess (DK) quasirelativistic approach. Both electron correlation and relativistic effects throughout the series are analysed and discussed. Final DK-CCSD(T) dipole moments are μ = 1.280, 1.598, and 1.764 a.u. for GeO, SnO, and PbO, respectively. Static dipole polarizabilities for the title molecules are α$_{zz}$ = 40.33, 56.29, and 62.55; α$_{xx}$ = 27.62, 37.74, and 37.46 a.u., respectively. Electron correlation effects are much more important than relativistic effects in the dipole moment and the parallel polarizability even in PbO. Only the perpendicular polarizability of PbO is more affected by relativistic effects than by the electron correlation. We note that the dipole moments and the parallel component of polarizability increase with the atomic number. No drop of the polarizability due to the relativistic effects, as it is common for atomic polarizabilities, is observed in the series of calculated molecules. The trends in static dipole polarizabilities within the series are analysed and compared with some related compounds containing a heavy atom.