Laser induced amplified spontaneous emission from the B2Π, L2Π, and I2Σ+ valence states of NO

Amplified spontaneous emission (ASE) from single rovibrational levels of valence (non-Rydberg) states of NO molecules has been investigated. The B2Π (v=24 and 25v=24 and 25), L2Π (v=5 and 6v=5 and 6), and I2Σ+ (v=6v=6) levels have been populated through laser optical–optical double resonance excitation via the Rydberg A2Σ+ state. Term values for the 2Π states have been determined with an accuracy of ±0.03 cm−1. Analyses of rotationally resolved dispersed ASE spectra in the near infrared region have shown that all the lower states belonged to the Rydberg states. The valence ∼Rydberg coupling in the upper manifolds has driven ASE systems from the valence to the Rydberg levels where they benefit from the strong intensities of inter-Rydberg transitions with Δv=0. The experimentally predicted valence ∼Rydberg interactions have been compared with theoretical treatments.