Knowledge Bank

A vacuum spectrometer with an Ebert mounting has been constructed. The spectra of ethyl fluoride, 1,1-difluoro-1-chloroethane, and n-propyl fluoride have been measured from $400cm-1$ to 70 $cm\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}1$. In ethyl fluoride the fundamental torsional vibration and two hot bands have been $measured.1$ The transitions have sharp Q branches and permit determination of both barrier height and shape. In general, the fundamental torsional oscillation is overlapped by hot bands and, unless sharp, intense Q branches exist, the analysis of the spectrum is complex.