Microwave Spectrum ofC12H4in the Ground Vibronic State

Abstract

The microwave absorption spectrum of a tetrahedral molecule in its ground vibronic state has been observed for the first time. By using a conventional Stark spectrometer with a signal averager, four lines with strengths≲5×${10}^{-11\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$ have been detected in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ${\mathrm{H}}_4$ between 7.8 and 14.2 GHz and identified as $\Delta J=0\mathrm{}$ transitions resulting from the distortion electric dipole moment.