Breakdown of the Point-Group Symmetry of Vibration-Rotation States and Optical Observation of Ground-State Octahedral Splittings ofS32F6Using Saturation Spectroscopy

It is shown that the mixing of vibration-rotation states by nuclear hyperfine interactions causes crossover resonances to appear in infrared saturation spectra. Examples are displayed in the ${\nu }_3$ band of S${\mathrm{F}}_6$ and obtain the tensor centrifugal-distortion constant $t_{044}$ and the tensor spin-rotation constant $c_d$. The value of $t_{044}$ (5.7 Hz) obtained is in excellent agreement with the theoretical value. A splitting is also demonstrated between vibration-rotation states which differ only in their parity.