Vibrationally excited state spectroscopy of radicals in a supersonic plasma

A plasma source based on a multilayer discharge geometry in combination wit h a time-of-flight REMPI experiment is used to study rotationally cold spec tra of highly excited vibrational states of mass selected radicals. The rov ibrational state distributions upon discharge excitation are characterised for the example of NO for ground state vibrational levels up to nu" = 18. W hereas rotational temperatures are lower than 50 K, a vibrational temperatu re of T-vib = 6700 +/- 700 K is found. (C) 2001 Elsevier Science B.V. Ah ri ghts reserved.