Rydberg states of NO in a magnetic field: Multichannel quantum defect approach of the linear Zeeman effect

Abstract

The linear Zeeman effect for the nf and np Rydberg states of NO has been analyzed in the intermediate energy region (n=7 and n=15). This analysis is based on a multichannel quantum defect treatment (MQDT), including the magnetic interaction, as proposed by Monteiro and Taylor [T. S. Monteiro and K. T. Taylor, J. Phys. B: At. Mol. Phys. 22, L191 (1989)]. The nonpenetrating nf states exhibit almost no channel mixing, but they are significantly perturbed by the Zeeman interaction within each rotational channel in a moderate field of 1 T. An excellent agreement has been found between the experimental results obtained in a 1 T magnetic field and the calculations, showing in particular the first manifestation of the Paschen–Back effect in a molecule. The penetrating np states of NO exhibit channel interaction, but, on the other hand, they are less perturbed by a 1 T magnetic field than the nf states are. Theoretical predictions have been made for a larger field strength of 5 T in the case of the 7p and 15p states.