Multiphoton Dissociation and the Fluorescence of Nitric Oxide in Intense Laser Fields

Abstract

The results are presented from experimental studies of the emission of NO radicals in a filament of femtosecond radiation produced in a N₂/NO₂ gas medium with total pressures of up to 1 atm. It is shown that in the recorded emission spectrum of the filament, emission transitions A²Σ⁺ (ν' = 0–2) – X²Π (ν'' = 0–5) of NO molecules are observed at concentrations of NO₂ gas of up to 10 ppb⁻¹. It is shown that the intensity of emission of NO A–X molecules grows along with the nitrogen pressure, due to the intermolecular nonradiative transfer of energy from the metastable \({{{\text{A}}}^{{\text{3}}}}\Sigma _{u}^{ + }\) level of a N₂ molecule to the electron A²Σ⁺ level of a NO molecule.