Knowledge Bank

Abnormally large e-f separations have been observed in the $(v1,0,v3)$ levels of the ground $X2\Pi g(3/2)$, state of $CuCl2$ about $2500cm-1$ above the lowest vibrational level (0,0,0). The largest splitting are accompanied by extra lines in the dispersed fluorescence spectra. Some of the extra lines have resolvable Cu hyperfine structure; they are assigned as transitions to levels winch result from mixing essentially between $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi g(1/2)$ and a nearby $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma g$ state. We have used an effective Hamiltonian to model the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi \sim 2\Sigma$ interaction and derived molecular constants for the unknown $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma$ state using a non-linear least-squares fitting routine. Taking an arbitrary value of the spin-orbit parameter $A\Pi$ of-$300cm-1$, we estimate the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma$ state to lie around $3000cm-1$ above the (0,0,0) level of the $X2\Pi g(3/2)$ ground state.