Vn. Markov et al., Microwave-submillimeter wave double-resonance spectrometer for the investigation of van der Waals complexes, REV SCI INS, 69(12), 1998, pp. 4061-4067
A double-resonance spectrometer, suitable for the investigation of low lyin
g intermolecular vibrational modes and of tunneling transitions of van der
Waals complexes, is described. The instrument utilizes a pulsed molecular b
eam Fourier transform microwave spectrometer (frequency range 4-26 GHz) for
signal detection, and a high frequency, phase stabilized, backward wave os
cillator (258 - 375 GHz), as well as a millimeter wave synthesizer (78 - 11
8 GHz), as pump radiation sources. A brief description of the Fourier trans
form microwave spectrometer and of the phase stabilization system of the ba
ckward wave oscillator is given. The experimental arrangement is such that
the molecular ensemble travels through the submillimeter radiation field pr
ior to the pulsed excitation microwave experiment, in which the resulting p
opulation changes are detected. The sensitivity and the resolution capabili
ties of the new technique are illustrated with double resonance spectra of
the van der Waals complexes Ar-CO and CO-N-2. (C) 1998 American Institute o
f Physics. [S0034-6748(98)01312-4].