Answer Happy

(a) Briefly comment on what is meant by the label "Fe K-edge"? Why is x-ray absorption spectroscopy referred to as an element specific technique? [2 marks) (b) An X-ray absorption spectroscopy study was performed on a prototype Na ion battery. In this battery, Na is stored in the oxide NaNiosMno.5O2. Briefly comment on what determines the amount by which the K-edge energy for Ni is higher than for Mn? Why was this study done using the K-edge instead of the L-edge? [2 marks]
(c) An "x-ray window" is a material which makes a "barrier" that is easy for X-rays to pass through. Briefly comment on what set of properties are favourable for a material to be used to make x-ray windows for an X-ray detector. [2 marks] (d) "Hard" X-rays are X-rays with energies of 10 keV or higher. Briefly comment on why hard X-ray absorption spectroscopy is a good technique for studying the active site of a Pt metal catalyst while catalytic reactions are being carried out? [2 marks] (e) For X-rays with energy corresponding to the U L-edge the mass absorption coefficient of U is u/ = 46.6. Show what will be the proportion of such X-rays that are transmitted through a layer of uranium oxide UO2 with thickness t = 10 microns. [Hint: the density of UO, is p = 10.97 g/cm. If you multiple this by the wt% of U in UO, you will get the effective density of U in UO2.] [2 marks]