Knowledge Bank

Various laser based spectroscopies, including R2PI (Resonance Two-Photon Ionization), LIF (Laser-induced Fluorescence), DF (Dispersed Fluorescence), and SEP (Stimulated Emission Pumping) have been utilized to determine several vibrational and rotational constants for the ground ($X~\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma g+$) and first singlet excited state ($A~1B1)$ of $\mathrm{<mrow\; data-mjx-texclass="ORD">7</mrow>}Li16O7Li$. From analysis of SEP spectra to ($\nu 1,\nu 2\ell ,\nu 3=0$) vibrational states, the $\mathrm{<mrow\; data-mjx-texclass="ORD">7</mrow>}Li16O7Li$ ground state is confirmed to be linear, with a bond length ($R0$) of $1.611\pm 0.005$ {\AA}. The $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}B1$ excited state is bent, with a bond angle of approximately $105\circ$, and a bond length ($R0$) of approximately 1.84 {\AA}. These geometries are consistent with ab initio estimates, and with the idea that the bonding in both these states is essentially ionic ($Li+1O-2Li+1$ and $Li+1/2O-1Li+1/2$, respectively).