Ionization potential of radium monofluoride

Abstract

The ionization potential (IP) of radium monofluoride (RaF) was measured to be 4.969(2)[10] eV, revealing a relativistic enhancement in the series of alkaline earth monofluorides. The results are in agreement with a relativistic coupled-cluster prediction of 4.981(7) eV, incorporating up to quantum electrodynamics corrections. Using the same computational methodology, an improved calculation for the dissociation energy (𝐷0) of 5.54(5) eV is presented. This confirms that RaF joins the group of diatomic molecules for which 𝐷0>IP, paving the way for precision control and interrogation of its Rydberg states.