Knowledge Bank

High resolution measurements of hyperfine structure on the $J=1\to 0$ transition in $CH353Cl$ were made using a molecular beam maser spectrometer. The measured $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl$ quadrupole coupling strength is $eQq=74753\pm 2$ kHz and spin-rotation constant $CCl=2.4\pm 0.5$ kHz. These results are compared with $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl$ quadrupole coupling strengths obtained for $CH2DCl$ and $CD3Cl$ and a systematic variation of coupling strength is noted and related to other properties of the molecule.