Kondo Resonance in PrTi2Al20: Photoemission spectroscopy and   single-impurity Anderson model
  The Kondo resonance at the Fermi level is well-established for the electronic structure of Ce (f1 electron) and Yb (f1 hole) based systems. In this work, we report complementary experimental and theoretical studies on the Kondo resonance in Pr-based f2 system, PrTi2Al20. Using Pr 3d-4f resonant photoemission spectroscopy and single impurity Anderson model (SIAM) calculations including the full multiplets of Pr ions, we show that an f2 system can also give rise to a Kondo resonance at the Fermi level. The Kondo resonance peak is experimentally observed through a final-state-multiplet dependent resonance and is reproduced with properly tuned hybridization strength in SIAM calculations. 
M. Matsunami, M. Taguchi, A. Chainani, R. Eguchi, M. Oura, A. Sakai,   S. Nakatsuji, S. Shin
cond-mat.str-el