Four-component relativistic calculations on the complexes between a water molecule and trivalent lanthanoid and actinoid ions Original Research Article

Complexes between a water molecule and trivalent lanthanoid and actinoid ions were investigated by all-electron four-component relativistic calculations using the Dirac–Hartree–Fock (DHF) method. DHF-based relativistic second-order Møller–Plesset perturbation (RMP2) calculations were also performed to incorporate electron correlation for the closed-shell systems. Non-relativistic calculations using the HF and MP2 methods were carried out in parallel to compare with the DHF and RMP2 results. Metal–oxygen distances and stabilization energies were evaluated, and a separability between relativity and correlation was found. Mulliken population analysis and spinor projection were used to analyze the wave functions, and a nature of coordinate bond was revealed.