Relativistic and correlation effects on molecular properties. I. The dihalogens F2, Cl2, Br2, I2, and At2
A benchmark study of a number of relativistic correlation methods is presented. Bond lengths, harmonic frequencies, and dissociation energies of the molecules F2, Cl2, Br2, I2, and At2 are calculated at various levels of theory, using both the Schrödinger and the Dirac-Coulomb-(Gaunt) Hamiltonian.