Broadband laser spectroscopy of RaF

With the advancement of spectroscopic techniques at radioactive beam facilities, the spectroscopy of radioactive molecules has been achieved in the past few years at ISOLDE (CERN) using the Collinear Resonance Ionization Spectroscopy (CRIS) experiment. The study of radioactive molecules is an emerging and promising discovery tool for diverse fields. Among them, diatomic polar molecules are at the center of theoretical and experimental investigations in search of the electron’s electric dipole moment (eEDM) and nuclear Schiff moments. Due to the strong electric field and the rich electronic, vibrational, and rotational structure inherent in molecules, the sensitivity to Schiff moments is expected to be enhanced in radioactive polar molecules, such as RaF. However, their molecular structure is poorly known, requiring preparatory spectroscopic studies of the electronic structure of the molecule. After two experimental campaigns at CRIS (2018, 2021), many electronic levels in RaF have been studied with broadband laser spectroscopy, as well as one optical transition in high resolution. This has shown the capacity of collinear laser spectroscopy at radioactive ion beam facilities for the study of radioactive molecules, as well as benchmarking the predictive power of state-of-the-art quantum chemistry. The present work focus on the analysis and retrieval of the molecular constant of the different electronic levels measured in the 2021 RaF campaign. To do so, PGOPHER has been implemented to simulate and fit the experimental spectrum retrieved. Furthermore, the influence of the population distribution in the measurement of the low-lying electronic states has also been studied, exhibiting a non-uniform cooling of the molecules arriving at CRIS