13 Feb/24
16:00 - 17:00 (Europe/Zurich)

Collinear resonant ionization spectroscopy of RaF


26/1-022 at CERN

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 [1].

Radioactive molecules are a promising discovery tool for diverse fields [2]. 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 [3-4]. 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 [5]. 

After three experimental campaigns at CRIS (2018, 2021, 2023), all predicted electronic levels in RaF have been studied with broadband laser spectroscopy and one optical transition in high resolution on 223,225,226RaF [6-7]. This has shown the capacity of collinear laser spectroscopy at radioactive ion beam facilities for studying radioactive molecules, as well as benchmarking the predictive power of state-of-the-art quantum chemistry.

Focusing on RaF as a case-study, this talk will present the study of eEDM on molecules, along with the basic principles of molecular spectroscopy. An overview of the CRIS technique and the features associated with the spectroscopy of radioactive molecules will also be presented.


[1] Garcia Ruiz, R.F., et al. "Spectroscopy of short-lived radioactive molecules." Nature 581.7809 (2020): 396-400.

[2] Opportunities for Fundamental Physics Research with Radioactive Molecules, arXiv:2302.02165 (2023)

[3] Kudashov, A. D., et al. "Ab initio study of radium monofluoride (RaF) as a candidate to search for parity-and time-and-parity–violation effects." Physical Review A 90.5 (2014): 052513.

[4] Osika, Y., & Shundalau, M. (2022). Fock-space relativistic coupled cluster study on the RaF molecule promising for the laser cooling. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 264, 120274.

[5] Flambaum, V. V., and V. A. Dzuba. "Electric dipole moments of atoms and molecules produced by enhanced nuclear Schiff moments." Physical Review A 101.4 (2020): 042504.

[6] S.-M. Udrescu, et al., Precision spectroscopy and laser-cooling scheme of a radium-containing molecule, nature physics (2023).

[7] S. G. Wilkins et al., Observation of the distribution of nuclear magnetization in a molecule, submitted (2023).