Molecular Ion Spectroscopy

We discuss our efforts to perform high-resolution spectroscopy of the BaCl$^+$ ion, an exciting candidate for ultracold molecular ion studies. This work details our search for a predicted predissociation channel between the first-excited $B^1\Sigma$ and $A^1\Pi$ states. It is expected that the rovibrational resolution afforded by predissociation spectroscopy will allow us to efficiently measure molecular-ion rovibrational temperatures. This is a crucial step in confirming our method to produce ultracold molecular ions via sympathetic collisions with a $^{40}$Ca MOT. To observe the predissociation of trapped BaCl$^+$, we detect slight increases in fragment Ba$^+$ with a novel time-of-flight device using radial extraction from a linear quadrupole trap.