USE OF LAMB--DIP TO OBSERVE THE TORSIONAL SPLITTING IN THE GROUND STATE OF HSSH

Abstract

With a Fabry-Perot cavity we have employed the saturation dip $technique^{1}$ to resolve and measure the torsional splitting of the ground state of HSSH. This splitting has previously not been observed within the resolution of a conventional millimeter $spectrometer.^{2}$ The measurements were made on various absorption lines of the $^{R} Q_{k{-1}}=0$ branch of the $H^{32} S^{32}SH$ species. The observed splitting of the lines is 125 KHz at 139.5 GHz, whereas the Doppler width for these lines is calculated to be 220 KHz. Extension of the measurements on HSSD are in progress. A discussion of the torsional barrier heights will be given.