Knowledge Bank

We have studied the electronic structure of C-Li and Si-Li in the $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\pi$ states using ab-initio SCF, MCSCF and Cl techniques. We find that both CLi and SiLi have $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$ ground states with the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\pi$ being 33 and 14 kcal/mol higher respectively. Potential energy curves and spectroscopic constants are presented for the title molecules and some speculation as to the possible consequences of the $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$ ground state of SiLi and CLi is indulged in.