We examined an equation-of-motion coupled-cluster (EOM-CC) method, which is basically equivalent to the SAC-CI method, starting from the generalized unrestricted Hartree-Fock (GUHF) wave function incorporated with a spin-dependent relativistic Hamiltonian. Demonstrations of the present method were carried out for the spin-orbit (SO) splitting energies of 3P and 2P states of relatively light atoms (Be - Ar). Although we considered only the lowest-order (c-2) Breit-Pauli one- and two-electron SO terms, it was found that the SO splitting energies calculated by the present method agree well with experimental ones, and are almost equivalent to those obtained by some conventional higher-order relativistic and electron-correlated methods.
Conformational analysis was conducted for a dizinc(II) complex cation [Zn2(bomp)(OCOMe)2]+ based on the DFT method, where bomp- represents a dinucleating ligand: 2,6-bis[bis(2-methoxyethyl) aminomethyl]-4-methylphenolate anion. The complex cation is enantiomeric, and when the twisted angle-an angle between a phenolate plane and a plane including two zinc(II) ions and a phenolic oxygen atom-is positive, the most stable conformation of the chelating rings is (+, δ, δ), where the first symbol represents the sign of the twisted angle and the second and third symbols represent the conformations of equatorial and axial chelating rings, respectively. Computational modeling was also conducted to construct the most stable structure of the complex cation without referring to the crystal structure. The model was constructed step by step using molecular mechanics and DFT methods. Ultimately, the most stable structure was successfully obtained.