HIGH RYDBERG STATES OF THE NO MOLECULE STUDIED BY 2-COLOR 4-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 A(2) Si gma(+) (upsilon' = 0, N' = 2) intermediate state in a supersonic jet. Rotational constants and term values are determined for the ns series (n = 8-13, upsilon = 0), while only term values are determined for the nf series (n = 7-10, upsilon = 0). Rotationally resolved structures o f the diffuse np series (n = 8-13, upsilon = 0) are observed.