Dynamics of Rydberg states of nitric oxide probed by two-color resonant four-wave mixing spectroscopy

Two-color resonant four-wave mixing (TC-RFWM) spectroscopy has been used to probe highly excited v=0 and v=1 Rydberg states of nitric oxide. Transitions to n=16–30, v=0, Rydberg states, and the 8p, 9p, 7f, 8f, 8s, and 9s, v=1 Rydberg states from the A 2Σ+, v′=0 and 1 states have been recorded. The decay rate of the 8p and 9p, v=1 states has been extracted from the observed line profiles by using a recently developed model for the excitation of quasibound resonances in TC-RFWM spectroscopy. Transitions from the A 2Σ+, v′=1 state to the X 2Π3/2, v″=10 state have also been observed, allowing an absolute calibration of the TC-RFWM signal intensity. This calibration is used to determine an excited-state absorption cross section for the 9p, v=1 Rydberg state.