CERN Accelerating science

(Color online) \textbf{a)} The two-step and three-step ionization schemes used in the experiments. Power-normalized, background-subtracted ion count rate as a function of total photon energy in $^{226}$Ra$^{19}$F for the \textbf{b)} two-step scheme and \textbf{c)} three-step scheme. The determined IPs are shown as vertical dashed-and-dotted lines with their statistical and total uncertainties as dark and light gray bands, respectively.

(Color online) \textbf{a):} Comparison of predicted theoretical and measured values for the IP of Group II monofluorides. Electron-impact (EI) \cite{Hildenbrand1965,Hildenbrand1968,Lau1989} and laser (L) measurements \cite{Berg1993,Jakubek1995} are denoted in the legend. The error bars for the laser measurements and theoretical predictions are smaller than the markers. \textbf{b):} Deviation, in standard deviations, between the theoretical predictions (dark blue squares) and experimental values (gray line). \textbf{c):} Comparison of experimental and theoretical values for the IP of $^{226}$RaF for increasing computational sophistication (left to right). An uncertainty is shown only for the most accurate theoretical value. The thin dark gray band and thick light gray band correspond to the statistical and systematic uncertainties on the experimental value for the RaF IP.

Schematic representation of IP fitting procedure. See text for details.

$\Delta\mathrm{(IP)}$ calculated as a function of distance from the ion detector (black line). The horizontal dashed line corresponds to the limit set at $\Delta\mathrm{(IP)}=0.1~\mathrm{cm}^{-1}$. Time-of-flight profile of $^{226}$RaF$^{+}$ ions in the three-step scheme experiment is shown as a histogram. The blue portion of the histogram was included in the data analysis whereas the red portion was excluded.