Hafnium

Hafnium is a transition metal with a valance of (IV) and forms a single oxide HfO2. The intensity ratio of the Hf 4f 7/2 and Hf 4f 5/2 peaks are constrained to 4:3. The two peaks are separated by a value of D= 1.71 eV. The Hf 4f 7/2 binding energy for the metal is found at 14.3 eV and is fit with an asymmetric peak-shape. The Hf 4f 7/2 binding energy for the oxide is found at between 16.7 to as high as 18.13 eV.

It should also be pointed out that the Hf 4s peak overlaps with the O 1s peak.


Table 1. Hafnium 4f7/2 binding energies (eV).

References:

[1] Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corporation, USA, Appendix B 1992.
[2] Naofumi et al, Applied Surface Science 253 (2007) 6844-6847.
[3] Smirnova et al, Journal of Physics and Chemistry of Solids 69 (2008) 685-687.