Knowledge Bank

Several transitions in the rotational spectrum of the $X2\pi (v=0)$ state of the $SO+$ ion have been observed. Discharges in $Ar-SO2,Ar-O2H2S$, or pure $SO2$ were employed to produce this species successfully. The very characteristic slow Zeeman effect of the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\pi 1/2$ state was used to unambiguously identify the $SO+$ lines, even though many stronger interfering lines of other species, both paramagnetic and diamagnetic, were present in the spectrum. The new spectroscopic constants agree well with previous values from optical spectroscopy.