THE MICROWAVE ZEEMAN SPECTRUM OF THE FREE SH RADICAL

Author Institution: National Bureau of Standards“Precise measurements have been made of the paramagnetic resonance spectrum of the free SH radical. The radicals are produced by the addition of hydrogen sulfide to the products of an electric discharge in wet hydrogen gas, a method, discovered by C.C McDonald. The spectrum is of the electric dipole type and arises from .A-type doubling transitions between Zeeman levels in the $^{2} \Pi _{sj2,} J = 3/2$ ground state of the SH molecule. A detailed spectral analysis yields the values $g_{j} = 0.83792 \pm 0.00002$ for the molecular g factor, $\nu_{\Lambda} = 111.42 \pm 0.04$ Mc for the $\Lambda$-typo doubling interval, and $|A_{1}| = 5.61 \pm 0.04$ Mc, $|A_{2}| = 0.08 \pm 0.04$ Me for the hyperfine structure coupling constants. The signal intensities depended critically on the relative flow rates of $H_{2}$ and $H_{2}S$, the best mixture being that which reduced the atomic hydrogen concentration to zero. Water vapor alone, when substituted for the wet hydrogen, gave reduced amounts of both atomic hydrogen and of SH.