Two-color multiphoton ionization and fluorescence dip spectra of NO in a supersonic free jet. Highly excited ns, np, nf Rydberg states

Abstract

The two-color multiphoton ionization (MPI) and fluorescence dip spectra due to the transitions from various rovibronic levels of the A 2Σ + state of NO to its high Rydberg states ( n = 6–46) have been measured in a supersonic free jet and rotational analyses have been carried out. It was found that the absorption cross sections from the A state to the h igh Rydberg states are proportional to 1/ n 3 ( n is the principal quantum number). Rotational analyses for the np and nf series indicated a gradual transition from Hund's case (b) to Hund's case (d) with the increase of n. The rotational structures of the nf complexes were found to be well reproduced by the long-range-force model. For ns and np complexes, however, the penetration effect is fairly large. A great dependence of the rotational constant upon n for the ns Rydberg states was found which has been predicted by Jungen and Miescher.