CCSD(T) study on the structures and chemical bonds of AnO molecules (An = Bk–Lr)*

Abstract

The molecular geometries and dissociation energies of AnO (An = Bk–Lr) molecules were first obtained at the coupled-cluster single-, double-, and perturbative triple-excitations [CCSD(T)] level of theory. Four hybrid functionals, B3LYP, M06-2X, TPSSh, and PBE0, were also employed in the calculations for the sake of comparison. In comparison of the CCSD(T) results, B3LYP, TPSSh, and PBE0 functionals can obtain more appropriate results than M06-2X and MP2. The analyses on molecular orbitals show that the 7s, 6d, and 5f atomic orbitals of actinide (An) atoms participate in the bonding of An–O bonds. The partial covalent nature between An and O atoms is revealed by QTAIM analyses.