PDN–FTMW spectroscopy of open-shell complexes

Abstract

Pure rotational spectra of a few Van der Waals complexes containing short-lived species have been observed in our laboratory. They are produced in a supersonic jet by using a pulsed-discharge-nozzle (PDN) system combined with a Balle–Flygare Fabry–Perot type Fourier-transform microwave (FTMW) spectrometer. Among the species so far observed, detailed analysis of Ar—OH is presented in this paper. This complex has unquenched orbital and electron-spin angular momenta, which couple with the large amplitude motion of the complex. Fine and hyperfine structures observed in the present study have been analysed on the basis of an internal-rotation model for the OH monomer hindered by a small anisotropic intermolecular potential.