Knowledge Bank

As a step towards measuring the electron electric dipole moment, we produce a sample of HfF$+$ using a two-color excitation. We promote HfF from $X2\Delta 3/2$ to an isotope and parity-selective intermediate state, and then to one of many highly perturbed Rydberg states from which it autoionizes to the vibrational ground state of HfF$+$. We measure the population of the rotational states of HfF$+$ using laser-induced fluorescence and find that only a small number of states are populated, with most of the population in $J\; \<\; 4$. Additionally, we see a strong propensity for autoionization to preserve the parity of the molecule, with one parity populating even $J$ levels and the other populating odd $J$. Using polarized light to prepare the Rydberg molecules in various orientations, and then probing the ion with LIF, we see that a polarization of $mJ$ sublevels also survives autoionization.