High Rydberg states of the NO molecule studied by two-color four-wave mixing spectroscopy

The ns, np and nf high Rydberg series of NO below the ionization limit are studied by two-color resonant four-wave mixing spectroscopy. The Rydberg states are prepared by two-step excitation through the A2Σ+ (v′ = 0, N′ = 2) intermediate state in a supersonic jet. Rotational constants and term values are determined for the ns series (n = 8−13, v = 0), while only term values are determined for the nf series (n = 7−10, v = 0). Rotationally resolved structures of the diffuse np series (n = 8−13, v = 0) are observed.