We have studied the $4d$ photoabsorption process of ${\mathrm{Eu}}^{+}$ ions by the linear-density-response theory with the density-functional theory and an optimized effective potential and self-interaction correction. Different from the recent experimental observation, which found that the $4d$ photoabsorption spectrum of ${\mathrm{Eu}}^{+}$ ions is almost the same as that of neutral Eu atoms, our calculated $4d$ photoabsorption spectrum of ${\mathrm{Eu}}^{+}$ ions shows many sharp and window resonances, which do not appear in case of neutral Eu atoms. The discrepancies between the experimental observation and our calculation are due to the experimental energy resolution. The convoluted spectrum with the experimental energy resolution is in good agreement with the experimental observation. Moreover, we predict the $4d$ photoabsorption spectra with several given energy resolutions, which call for a further higher-resolution experiment.

• Received 22 December 2000

DOI:https://doi.org/10.1103/PhysRevA.64.032716