REMPI studies in the Lewis-Rayleigh afterglow of nitrogen

Abstract

The resonance-enhanced multiphoton ionization (REMPI) technique has been used to detect the presence of highly vibrationally excited nitrogen (to at least ν″ = 26) in the Lewis-Rayleigh afterglow of nitrogen using photoionization via the intermediate a 1Π g state (Lyman-Birge-Hopfield bands). For the ν″ = 23, 24 and 25 levels in their Δν = −11 sequence, the REMPI process involves one photon to excite and one to ionize in contrast to the 2 + 2 process required to detect the ν″ = 0 level. The power dependences of the various processes have been measured and provide further confirmation of the assignments.