Reassessment of the first ionization potentials of copper, silver, and gold

The first ionization potentials ($V_{\mathrm{IP}}$’s) of copper, silver, and gold have been reassessed using a two-color resonant excitation scheme on laser-vaporized atomic beams of Cu, Ag, and Au. Rydberg levels of the ${\mathrm{nd}}^{10}{n}_R{s}^1{(}^2{S}_{1/2})$ and ${\mathrm{nd}}^{10}{n}_R{d}^1{(}^2{D}_{3/2,5/2})$ series converging to the ground ${}^{1}S$ term of the singly charged cations were excited and pulse-field ionized. The fit to the Rydberg levels yielded the ionization potentials $V_{\mathrm{IP}}\mathrm{}\left(\mathrm{Cu}\right)\mathrm{}=62\mathrm{}317.3\left(2\right)\mathrm{}{\mathrm{cm}}^{\mathrm{-}1},$ $V_{\mathrm{IP}}\mathrm{}\left(\mathrm{Ag}\right)\mathrm{}=61\mathrm{}106.45\left(20\right)\mathrm{}{\mathrm{cm}}^{\mathrm{-}1},$ and $V_{\mathrm{IP}}\mathrm{}\left(\mathrm{Au}\right)\mathrm{}=74\mathrm{}409.0\left(2\right)\mathrm{}{\mathrm{cm}}^{\mathrm{-}1}.$ A comparison of these results to the currently accepted values revealed slight discrepancies to the previously reported IP of silver.