Vibrationally excited state spectroscopy of radicals in a supersonic plasma

A plasma source based on a multilayer discharge geometry in combination with a time-of-flight REMPI experiment is used to study rotationally cold spectra of highly excited vibrational states of mass selected radicals. The rovibrational state distributions upon discharge excitation are characterised for the example of NO for ground state vibrational levels up to v″=18. Whereas rotational temperatures are lower than 50 K, a vibrational temperature of Tvib=6700±700 K is found.