Showing posts with label Workshop Exercises. Show all posts
Showing posts with label Workshop Exercises. Show all posts

Workshop Exercises: Advanced Chemical State Analysis

1) Carbon 1s - Set up a standard file for the fitting of adventitious carbon. Download the C 1s spectrum here.


2) Use it to charge correct a series of spectra. Download test file.


3) Oxygen 1s - General fitting of the O 1s spectra for metals.  Use file from number 2. Fit the O 1s spectrum, understand and explain all sources of oxygen.


4) Ti 2p - Set up curve-fitting parameters.  Download Ti 2p test file. See titanium literature fitting values.


5) Cr 2p - Set up curve-fitting parameters. Download Cr 2p test file. See chromium literature fitting values.


Notes:
•Cr(VI) Species – mix of oxide and hydrated species
   -One narrow peak FWHM 1.5 eV
  -Range from 579.0 to 580.0 eV
•Cr(III) Species – mix of oxide and hydrated species
  -Cr(OH)3 - One broad peak FWHM of ~2.5 eV, set to 577.5 eV
  -Cr2O3 - Five multiplet peaks of equal FWHM (~0.9 eV) with set areas and separations based on standard sample
•Cr(0) – Metal
  -One asymmetric peak with a FWHM of 0.9 eV
  -Range from 573.9 to 574.5 eV

6) Ni 2p - For the brave, download and give it a try. See Ni 2p literature fitting values and general instructions here.



Workshop Exercises: The Auger Parameter and Wagner Plots

The Auger Parameter

1. Try calculating the Auger parameter for ZnO and Cd metal (click on links to download the spectra). (Compare to zinc and cadmium literature.)
2. Calculate the Auger parameter and use it to determine the chemical state for 3 unknown Cu species (Unknown 1, Unknown 2, Unknown 3).  Click here to access Cu binding energy and Auger parameter values.

Wagner Plots
Handouts will be given or you can download the exercise here.


Use lines of slope 1 and 3 to look at the trends:
1) For the Ga(III) halogen series.
2) Going from Ga(III), Ga(II) to Ga(I).
3) For the metal, alloys and semiconductors (Ga2O3 is also a semiconductor).
Do final state effects dominate (slope of 3) or do initial state effects dominate (slope of 1)?