Isotope Effect in the O2 and SO Molecules

Abstract

The rotational energy, spin-orbit coupling, spin-spin coupling, and the coupling between the molecular rotation and the electron spin are taken into account up to the second order perturbation in the Born-Oppenheimer approximation. The resulting expressions of coupling constants, such as Be, De, α, αD, λe, λD, λDD, αλ, αλD, αλDD, γe, γD, αγ, αλD, in the effective Hamiltonian show specific dependences on the reduced mass µ of the diatomic molecule under consideration. The theory is tested for 13 molecular parameters for the O2 isotope molecules and 8 molecular parameters for the SO isotope molecules and they all agree with experimental data within the presently available accuracy.