Ab initio spin-orbit calculations on the lowest states of the nickel dimer

摘要

Potential energy curves of the lowest electronic states of the Ni _2 dimer are calculated near the equilibrium using the multireference ab initio methods including the spin-orbit interaction. Scalar-relativistic results fully confirm previous qualitative interpretations based on the correlation with atomic limits and the symmetry of vacancies in the atomic 3d ~9 shells. Spin-orbit calculations firmly establish the symmetry of the ground state as _g~0 and give the excitation energies 70 ± 30 cm -1 and 200 ± 80 cm ~(-1) for the lowest 0 _u~- and 5 _u states, respectively. The model electronic spectrum of the Ni _2 shows some trends that might be observed in matrix isolation far-infrared and electron spin resonance spectra.