Knowledge Bank

Direct observation of the $J=2\leftarrow 1$ fine structure transition in $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}PN+$ and the $J=3/2\leftarrow 1/2$ transition in $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}PC+$ by far-infrared laser magnetic resonance spectroscopy has led to the precise evaluation of these fine structure splittings and corresponding $gJ$-factors and hyperfine parameters. These values are expected to facilitate the observation and analysis of these transitions in the interstellar medium.