Ab initiopseudopotential and density-functional all-electron study of ionization and excitation energies of actinide atoms

Both relativistic energy-consistent small-core ab initio pseudopotential and fully relativistic density-functional all-electron calculations have been carried out by exploiting the presently available highest computational capability for the first to fourth ionization potentials as well as the $\mathrm{df}$ $[{\Delta }_{\mathrm{df}}\hspace{0.5em}=\hspace{0.5em}{E(f}^n{d}^1{s}^2{)-E(f}^{n+1\mathrm{}}{d}^0{s}^2)$ ($n=0\mathrm{}-13$ for Ac–No)] and $\mathrm{fd}$ $[{\Delta }_{\mathrm{fd}}\hspace{0.5em}=\hspace{0.5em}{E(f}^n{d}^2{s}^2{)-E(f}^{n+1\mathrm{}}{d}^1{s}^2)$ ($n=0\mathrm{}-13$ for Th–Lr)] excitation energies for the whole series of actinide atoms. The calculated ionization potentials might be useful to guide future experimental measurements.