The measurement of widths and pressure-induced shifts of rotational lines in the microwave region

Abstract

Using double phase-locked source-modulated microwave spectrometers operating at frequencies up to 110 GHz and at gas pressures to 30 mTorr, pressure-induced widths and shifts have been measured for lines in the spectra of OCS CH3Cl, CH3OH, CH3CN and CH3I. Results are given for foreign-gas broadening and shifting as well as self-perturbation for the first four gases. The results differ between the two classes of lines observed, those due to transitions between rotational energy levels and those between levels created by hindered motion.