Origin of Double Peaks in Photoemission Spectra from Metallic Ce-Compounds

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The photoemission spectra are calculated for the Anderson impurity model extended to include the excited spin-orbit multiplet ²F_7⁄2 located at about 0.3 eV above the ground multiplet ²F_5⁄2 of Ce³⁺(f¹) ion. A relatively large peak appears about 0.3 eV below the Fermi energy due to the relaxation of conduction electron to the ²F_7⁄2 state, along with a broad peak due to the excitation from the 4f level and a small peak at the Fermi energy which is directly related with Kondo anomalies in low energy phenomena. The small peak disappears at room temperatures, but the peak at 0.3 eV does not, and thus the discrepancy between the peak intensity in photoemission and T_K estimated from low energy phenomena is partly removed.