An all-electron Hartree—Fock investigation of the electronic structure and nature of bonding in the molecule YPd

Abstract In the present investigation we present all-electron ab initio Hartree—Fock (HF) calculations of the three low-lying electronic states 2 Δ, 2 Σ + , and 2 Π resulting from the interaction between an yttrium atom in the 2 D4d 1 5s 2 term and a palladium atom in the 1 S4d 10 term. The basis sets used were of double-zeta quality in general, but the 4d orbitals were represented by triple-zeta functions. The chemical bond in all three states can be attributed to donation of charge from the filled dσ and dπ orbitals of the Pd atom into the empty or partially filled dσ and dπ orbitals of the Y atom and a back-donation of charge from the filled 5s orbital of Y into the empty 5s orbital of Pd. The bonding in the YPd molecule produces a small negative charge on the Y atom. Dipole moments of 0.52, 0.37 and 0.61 D, respectively, have been predicted for the 2 Δ, 2 Σ + and 2 Π states. Equilibrium distances, dissociation energies and vibrational frequencies have been calculated for the low-lying states of YPd.