Rydberg states of OH radical

We study Rydberg states of radical in adiabatic (rotational Born-Oppenheimer) approximation as well as in the inverse limit. The needed value, d = 0.833, of the OH+ cation's dipole moment was calculated using the RCCSD(T)/aug-cc-pV5Z. Our calculations show that a dipole moment of this magnitude influence weakly on the energies of the Rydberg states. The exception are the states originating from s-states in the central-symmetric field, which are influenced significantly by the cation dipole moment. In the inverse Born--Oppenheimer limit, we study in detail the dependence of the Rydberg spectrum upon the total angular momentum, J, of the molecule. This dependence substantially differs from the well-known dependence, ~ J(J+1), of the rotator energy on its total momentum. Keywords: polar molecules, multipole moments, polarizability, hydroxyl.