Broadband velocity modulation spectroscopy of HfF+: Towards a measurement of the electron electric dipole moment

► Broadband velocity modulation spectroscopy of HfF+. ► Frequency comb and tunable single-frequency laser both used for investigation. ► Nineteen bands over a spectral range of 5000 cm−1 and nine electronic states characterized. ► High-precision rotational constants, lambda-doublings, and isotope shifts. ► HfF+ will be used to search for the permanent electric dipole moment of the electron.