(VUV+UV)-REMPI Detection of the Methyl Radical Product in a Crossed-beam Scattering Experiment

A (VUV+UV)-REMPI spectroscopy scheme was exploited to detect the methyl radical (CH3). To demonstrate its high sensitivity, a crossed-beam scattering experiment was conducted with CH3(CD3) as the reaction product from F+CH4(CD4). The absolute detection limit was estimated to be about 107/cm3. From the observed spectra, the spectroscopic constants of the two intermediate Rydberg states, 3d 2E″ and 3d 2A1′, were also refined.