SUB-MILLIMETER-WAVE SPECTROSCOPY OF THE AR-CENTER-DOT-H-3(-CENTER-DOT-D-3(+) IONIC COMPLEXES() AND AR)

An investigation of the sub-millimeter-wave spectra of the ionic compl exes Ar . H-3(+) and Ar . D-3(+) is presented. These complexes were pr oduced in a negative glow electric discharge, in mixtures of argon wit h either H-2 or D-2. About 80 new transitions were assigned iu the 455 -650 GHz frequency range using a sub-millimeter-wave spectrometer buil t with Russian made backward wave oscillators (BWO) sources. These mea surements enabled us to observe the first K-a = 2 transitions for Ar . H-3(+) and the first K-d = 3 transitions for Ar . D-3(+). Analyses of the line frequencies were carried out using an IAM-Iike approach, whi ch accounts for the large amplitude internal rotation motion displayed by both species. Insights into the geometry of the intermediate confi guration for this large amplitude motion were gained. (C) 1998 Academi c Press.