Knowledge Bank

The rotational spectra of the $\mathrm{<mrow\; data-mjx-texclass="ORD">7</mrow>}LiO$ radical in the $v=0$ and $v=1$ vibrational states were observed in millimeter and submillimeter wave region. The LiO radical was generated by the reaction of lithium vapor with $N2O$ in a heat pipe cell. The rotational and centrifugal distortion constants, -type doubling constants, spin-orbit interaction constant, and hyperfine interaction constants were derived through analysis of the rotational spectra observed in the present study, combined with the radio-frequency spectra of -type transitions reported by S. M. Freund $etal.1$ The LiO radical was confirmed to have a $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi i$ ground electronic state with an exceptionally large -type doubling constant, as in the case of NaO. A pure precession hypothesis applied to the observed ``p'' constant gives the $\Sigma -\Pi$ energy separation to be $2565cm-1$.