Knowledge Bank

Experimental results from our continuing study of the Rybderg states of Calcium Monochloride will be presented. Previously we have characterized the quantum defects and predissociation mechanisms of core-penetrating $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ states of CaCl in the $n\ast =3-7$ $region.a,b$ Questions unanswered by this work propelled further studies of the low-$n\ast$ region $(n\ast =3-5)$ by REMPI and ion-dip techniques, as this region is expected to be extensively predissociated by $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi$ repulsive states. Interest in high-$n\ast (n\ast >15)$ Rydberg states of CaCl has also fueled further REMPI experiments near the first ionization threshold $(48491cm-1)$. Studies of the low-$n\ast$ region failed to reveal several predicted members of known core-penetrating $2\Sigma +$ Rydberg series $(n\ast =0.16,0.49,0.682\Sigma +$ and $0.302\Pi$), while preliminary data for the high-$n\ast$ region above the $\nu +=0$ IP indicate the presence of vibrationally autoionizing Rydberg states converging to $\nu +>0$ vibrational levels of the $CaCl+$ ion $X1\Sigma +$ state. Analysis is ongoing.