Far-infrared self-broadening and pressure shift measurements of methyl cyanide

Pressure shifts and self-broadening parameters of the J=43←42, J=44←43, J=56←55 and J=68←67 sub-bands of the1A1 ground state of CH3C14N up to K=10 were determined using the NIST tunable far-infrared (TuFIR) spectrometer. The pressure shift agrees well with theoretical predictions made using Anderson-Tsao-Curnutte theory. The self-broadening parameter shows the expected K depencence. However, the predictions are systematically too large for decreasing J. The influence of the TuFIR power spectrum on the derived experimental parameters was evaluated and a comparison was made between two-wave and three-wave mixing spectroscopy.