Ionization potential of radium monofluoride

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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mo>(</a:mo> <a:msub> <a:mi>D</a:mi> <a:mn>0</a:mn> </a:msub> <a:mo>)</a:mo> </a:math> of 5.54(5) eV is presented. This confirms that RaF joins the group of diatomic molecules for which <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"> <b:mrow> <b:msub> <b:mi>D</b:mi> <b:mn>0</b:mn> </b:msub> <b:mo>&gt;</b:mo> <b:mi>IP</b:mi> </b:mrow> </b:math> , paving the way for precision control and interrogation of its Rydberg states.