Knowledge Bank

Measurements of the rotational spectrum of H$2$$\mathrm{<mrow\; data-mjx-texclass="ORD">33</mrow>}$S, detected in natural abundance, were performed in the 200 GHz - 1.072 THz frequency range. The Lamb-dip technique was employed to exploit sub-doppler resolution and thus to resolve the hyperfine structure of the rotational lines. The retrieved transition frequency values allowed us to revise the $\mathrm{<mrow\; data-mjx-texclass="ORD">33</mrow>}$S spin-rotation tensor as well as to improve the $\mathrm{<mrow\; data-mjx-texclass="ORD">33</mrow>}$S quadrupole-coupling and centrifugal-distortion constants. Furthermore, the rotational spectrum of the main isotopopologue was investigated in the THz frequency regime. The Lamb-dip technique was employed as well in order to obtain sub-doppler resolution in this frequency region and thus to provide transition frequency values at 1 THz with an accuracy of 1 kHz.