THE PURE ROTATIONAL SPECTRUM AND HYPERFINE STRUCTURE OF $HC\ell ^{+}$ STUDIED BY LASER MAGNETIC $RESONANCE^{\ast}$

Abstract

Pure rotational transitions have been measured for the $HC\ell ^{+}$ molecular ion by the technique of far-infrared laser magnetic resonance spectroscopy. The ions were generated in an intracavity discharge through helium containing a trace of $HC\ell$ at total pressures near 1 Torr. Measurements have been made for the $H^{35}C\ell ^{+}, H^{37}C\ell ^{+}, D^{35}C\ell ^{+}$, and $D^{37}C\ell ^{+}$ isotopes at magnetic flux densities up to 20 kGauss. These spectra are being analyzed according to the $^{2}\Pi$ Hamiltonian of Brown.