Knowledge Bank

The $Na233\Pi g$ and $43\sum y+$ state dissociate adiabatically to the 3s+4p atomic limit. Energy levels below the 3s+3d atomic limit of these two states have been observed by perturbation facilitated optical-optical double resonance (PFOODR) fluorescence excitation $spectroscopy.[m,n]$, Energy levels above the 3s+3d atomic limit could not be observed by detecting molecular fluorescence but have been observed recently by detecting atomic $3d\to 3p$ fluorescence. The $33\Pi g$ and $43\sum g+$ states ineract with the $3s+3d23\Pi g$ and $33\sum g+$ states, respectively. As a result of the perturbation the $33\Pi g$ state strangly predissociates and the linewidth of levels close to the 3s-3d limit is about $15cm-1$. The $43\sum g+$ state is weakly predissociated.