All-electron [Formula Presented] self-consistent-field calculations of relativistic effects in the molecular properties of [Formula Presented],[Formula Presented], and [Formula Presented] molecules

Relativistic effects in the binding energy, the bond length, and vibrational frequencies of ground-state potential-energy curves are investigated for [Formula Presented],[Formula Presented], and [Formula Presented] by performing relativistic and nonrelativistic all-electron Dirac-Fock-Slater [Formula Presented] calculations. Wave functions from numerical solutions of Dirac(Hartree)-Fock-Slater equations for atoms are taken as basis sets. A variationally consistent approximation for the direct Coulomb potential has been used for efficiently obtaining accurate potential energy curves. Our calculations confirm that the spin-orbit effect weakens the binding of the 6p-element molecules [Formula Presented],[Formula Presented], and [Formula Presented].