Transport properties of N + N, O + O, N + O, C + O, C+ + O, C + N, and C + C using an accurate treatment of nonzero spin and electronic angular momentum and including spin–orbit interaction

We have carried out first principles calculations of transport properties of the title atom-atom systems using accurate ab initio electronic structure methods and quantum scattering. We go beyond the Born-Oppenheimer approximation and show how one can properly include the spin and orbital angular momentum of atoms in the calculations. We give the explicit transformation between coupled LS atomic states, where L is the total electron angular momentum and S is the total spin angular momentum, and the diatomic Hund's case (a) basis. We include both Coulomb spin-orbit interaction as well as the effect of the magnetic-moments of the electrons via the Breit interaction. The relations between the long-range forces of different symmetry electronic states are given for S + P and P + P asymptotes.