2024

Athanasakis-Kaklamanakis, M.; Wilkins, S. G.; Lassègues, P.; Lalanne, L.; Reilly, J. R.; Ahmad, O.; Au, M.; Bai, S. W.; Berbalk, J.; Bernerd, C.; Borschevsky, A.; Breier, A. A.; Chrysalidis, K.; Cocolios, T. E.; de Groote, R. P.; Fajardo-Zambrano, C. M.; Flanagan, K. T.; Franchoo, S.; Garcia Ruiz, R. F.; Hanstorp, D.; Heinke, R.; Imgram, P.; Koszorús, Á.; Kyuberis, A. A.; Lim, J.; Liu, Y. C.; Lynch, K. M.; McGlone, A.; Mei, W. C.; Neyens, G.; Nies, L.; Oleynichenko, A. V.; Raggio, A.; Rothe, S.; Skripnikov, L. V.; Smets, E.; van den Borne, B.; Warbinek, J.; Wessolek, J.; Yang, X. F.

The radiative lifetime of the 𝐴2Π1/2 (𝑣=0) state in radium monofluoride (RaF) is measured to be 35(1) ns. The lifetime of this state and the related decay rate Γ=2.86⁢(8)×107 s−1 are of relevance to the laser cooling of RaF via the optically closed 𝐴2Π1/2 ← 𝑋2Σ1/2 transition, which makes the molecule a promising probe to search for new physics. RaF is found to have a comparable photon-scattering rate to homoelectronic laser-coolable molecules. Owing to its highly diagonal Franck-Condon matrix, it is expected to scatter an order of magnitude more photons than other molecules when using just three cooling lasers, before it decays to a dark state. The lifetime measurement in RaF is benchmarked by measuring the lifetime of the 8⁢𝑃3/2 state in Fr to be 83(3) ns, in agreement with literature.