Knowledge Bank

The pure rotational spectra of VN (X $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Delta r$) and VO (X $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$) in their ground electronic states have been recorded in the frequency range 295-525 GHz. In each case, seven rotational transitions were measured. Fine structure and vanadium hyperfine splittings were resolved in these data. These radicals were produced by reacting gas-phase VCl$4$ with N$2$ (VN) or residual O$2$ (VO) in an AC discharge. Rotational, fine, and hyperfine constants were determined. In particular, the hyperfine constants \textit{a}, \textit{b}, and \textit{c} for VN have been established from a global fit to the spectra. The parameters obtained are in good agreement with previous studies.