OBSERVATION OF AROH IN A PULSED DISCHARGE SYSTEM

The free-radical complex ArOH has been generated in a pulsed electric discharge in a supersonic free-jet expansion of argon and water vapour. Both OH and ArOH are found to be rotationally cold but vibrationally excited OH was also observed. The laser-induced fluorescence excitation spectrum of the complex is similar to that reported by other workers but shows a series of satellite bands to the red of the main progression which have no discernable rotational structure at Doppler-limited resolution. As these bands increase in intensity as the effective temperature of the complex is raised, they are tentatively assigned to transitions arising from vibrationally excited van der Waals levels in the ground state. © 1990.