Origin of Anomalies in Photoemission from the Conduction Band of Potassium
Solid State Communications
Above the threshold for K 3p excitation, the conduction band photoemission spectrum of metallic potassium is dominated by core excitation coupled to autoionization. This accounts for the observation of a strong response in regions where k-conserving transitions are forbidden, as well as for the angle- integrated character of data taken in an angle-resolved mode. The anomalous triangular peak at the Fermi level observed with photon energies near 25 eV is due to the selective enhancement of the 4p character of the conduction band by autoionization involving electrons excited into the normally empty 3d bands.
G.K Wertheim, D.M Riffe, Origin of anomalies in photoemission from the conduction band of potassium, Solid State Communications, Volume 96, Issue 9, December 1995, Pages 645-648, ISSN 0038-1098, http://dx.doi.org/10.1016/0038-1098(95)00528-5.