Photoassociation and ionization spectroscopy of ultracold $^{7}$Li-$^{85}$Rb molecules

We measured $^{7}$Li-$^{85}$Rb vibrational levels in the d$^{3}\prod $ electronic state through laser spectroscopy of ultracold molecules. In a dual species MOT, we bind pairs of ultracold atoms via photoassociation (PA). Our molecule formation rate can be as high as 3.5 x 10$^{7}$ s$^{-1}$ for the v$=$3 line of the 3(0$^{+})$ state and our PA rate coefficient, 1.3 x 10$^{-10}$ cm$^{3}$/s, is the highest among heteronuclear bi-alkali-metal molecules. These excited molecules decay to a triplet (a$^{3}\sum^{+})$ ground state; once there, they are detected using resonantly-enhanced-two-photon-ionization (RE2PI). Using known ground state vibrational levels we are able to determine the vibrational levels of the d$^{3}\prod $.