Knowledge Bank

This talk summarizes experimental results from recent ion-dip spectroscopy studies of CaCl as well as previously unpublished optical-optical-double-resonance work with specific regard to predissociation processes of $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ Rydberg states in the low- region. A single repulsive state (assigned as $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$) was found to be responsible for all observed predissociations of $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ Rydberg states. The $n\ast$-dependent internuclear distances of the intersections between Rydberg and repulsive $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ states were determined through the use of trial-and-error Franck-Condon calculations. Values of the $n\ast$-scaled electronic matrix elements governing the Rydberg $\leftrightarrow$ repulsive state interaction were obtained from the measured linewidths and computed Franck-Condon densities. With the assumption of a one-parameter form for the repulsive curve. $E(cm-1)=C\ast \ast \ast R\ast \ast \ast +De,$ where $C12$ has the units $\backslash AA\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}cm-1$ and $De=33171cm-1$ for CaCl, the optimum values of $C12$ was found to be $2.354\times 108\backslash AA\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}cm-1$.