ϵf(B1) is the bare 4f binding energy of the Kondo related bulk peak, Δav(B1) the average hybridization of the Kondo related bulk peak, nf the number of 4f electrons for the Kondo related peak, TK the Kondo
temperature, and χm(0) the Pauli magnetic susceptibility at 0 K. ϵf(B2) is the bare 4f binding energy of the non-Kondo related bulk peak, Δav(B2) the average hybridization of the non-Kondo related bulk peak, and ϵf(S) is the bare 4f binding energy of a surface peak. INK and IK are the intensity of the non-Kondo related bulk peak and the Kondo related bulk peak, respectively. IS and IB are the intensity of the surface peak and the bulk peak, respectively. Here, IB=INK+IK.