These links may provide some useful information:

http://www.chem.qmul.ac.uk/surfaces/scc/scat5_3.htm

http://www.sciencedirect.com/science/article/pii/S0169433200004438

http://pubs.acs.org/doi/abs/10.1021/es100547q

You can  find in several handbooks on XPS, how to use the XPS spectra for oxidation state determination. Normally, the binding energies measured in XPS depend on the surrounding chemical environment of atoms.   

The Oxidation state of any element/ ion from XPS by matching the binding energy positions of observed spectrum to reported literature.e.g handbook of XPS. The list of BE position is  also available in websites. References are already given in other answers.

Thank to all of u for given important suggestions.

I agree with Ram, it is not a "calculation", first you calibrate the energy of your measurement correctly (if it is taken at a synchrotron) to be able to compare to literature, then you fit your background, and your peaks with voigt profiles. From the position of the peaks (energy) you know the oxidization state comparing to literature. If you have several peaks overlapping in the same measurement (so several oxidation states in you compound) you can compare the area ratio of the fits which gives you after correcting with the sensitivity factors the ratio of the oxidation states.

Dear Paresh:

 Only a brief comment on the XPS oxidation state question.

 As the other participants suggested, there are books,  internet sites that provide comprehensive information on the question you have asked. It is not possible to provide a short and simple answer to such a general question, so you need to read and study the basics,  to work with scientific rigor, that allow properly process the data from the XPS spectroscopy.

 In general terms, surface characterization techniques are not simple techniques, since complex phenomena are involved, that should be analyzed and studied, to have a comprehensive overview of a powerful analytical technique such as XPS.

 The XPS experiment allows us to measure the kinetic energy of the photoelectrons extracted or emitted from the sample or solid, within the energy range that allows the X-ray source.

Therefore is possible through the principle of conservation of energy, using the kinetic energy and other physical constants, deduct or calculate the binding energy of the photoelectrons.

Each element of the sample, shows a characteristic binding energy corresponding to the atomic orbital from which is being emitted. Therefore for each element, we get a package of the characteristic peaks,these peaks appear in the XPS spectrum.

 But the binding energy of photoelectrons depends on several aspects, so that not only the atomic orbital, plays a role, there are other relevant aspects such as the formal oxidation state and the physico-chemical environment, all of them affect the binding energy.

Once you have the corresponding spectra of the elements of interest, you must follow some steps (as binding energy referencing (there are different possibilities), fitting routines in some cases, etc, to obtain the binding energy of each element.

 With these values of binding energy, you can search on the public XPS databases as the NIST or the LaSurface, if you don´t have any other sources , the binding energy  experimentally obtained and search the correspondence with the binding energy values  registered in the database, for assigning the peaks.

 As a rule the atoms of a higher positive oxidation state will show a higher binding energy due to the extra coulombic interaction between the photo electron and the atom core, compared to the binding energy  of the elemental atom. But, the most relevant is maybe  you will need read, learn, and continously work on the XPS data to get a proper chemical state assignment.

 The links of the open access XPS databases are:

NIST: http://srdata.nist.gov/xps/

LaSurface: http://www.lasurface.com/accueil/index.php

Webs with useful XPS Data and fundamentals:

ThermoScientific: http://xpssimplified.com/periodictable.php

Surface Science Western Laboratories: http://www.xpsfitting.com/

X-ray Photoelectron Spectroscopy International http://www.xpsdata.com/

XPS processing software

CAsaXPS: A Beginners Guide to CasaXPS http://www.casaxps.com/cam7/BeginnersGuide/ABeginnersGuideToCasaXPS.htm

Books:

Practical Surface Analysis - Auger and X-ray Photoelectron Spectroscopy

D. Briggs and M. P. Seah (Editors), Wiley Interscience, 1990 (2nd ed.)

Surface Analysis: The Principal Techniques John C. Vickerman

An Introduction to Surface Analysis by XPS and AES 2nd Edition

by John F. Watts and John Wolstenholme 

Hi,

Firstly find the binding energies of elements after proper calibrations (Take C-1s (284.6eV) as reference).

After that you can easily compare your B.E. with literature 

Christian Urban Hi. Can you please mention where can one find the sensitivity factors of oxidation states. I know about RSFs for atoms but no idea if there are sensitivity factors for oxidation states as well. Or do you mean the same sensitivity factors for different peaks eg doublets in Fe where one has 2p 3/2 and sp 1/2 and you calculate the oxidation state ratios from one peak (2p 3/2). Is it necessary to apply RSF to 2p 3/2 if you are determining the oxidation states ratio from just that peak? How to apply it and in the other case, can we just add the peak areas from both peaks (2p 3/2 and 2p 1/2 for example in Fe's case) and simply find the ratio?

My answer is comming late, but I´ll will answer anyway.

Sensitivity factor in XPS, are not an unique set. Relative sensitivity factors are required to quantify the elements in the XPS spectra.

These RSF coefficients help to scale the peak areas to give us a number referredto the amount (in Atomic percent) of the element at the sample´s ​surface.

There are several RSF sets ,the most extended are Scofield and Wagner (we should be sure the RSF sets (if included in the software) corresponds to the X-Ray anode used, I mean there are sets of RSF for the differents X-Ray anode source (Aluminum or Magnessium are the most wide spread).

Beside the RSF sets mentioned some software/equipments developers, include their own set of RSF factors.

A survey XPS spectra some times can be complex if many elements are present, and if there is overlaping betwee some lines, the RSF set of factor will contain, not only the RSF factor for the main lines also for the doublets, making easy quantify avoiding the overlapped lines, that´s mean the set will include for example RSF factors for Fe2p but also for Fe2p3/2 and Fe2p1/2.

Is relevant to select the RSF for the peak selected. If you draw the baseline under the Fe2p3-Fe2p1 doublet, you will need the Fe2p RSF, but if you draw the baseline under Fe2p3/2, then you will select the Fe2p3 RSF.

RSF factors are only required on the survey spectrum when quantify the elements.

The software also allows to draw the baseline to define the area under the peak, and fi nally by the RSFs and the correct transition asignation, you will be able to identify, and quantfy the elements on the surface, whatever is the "chemical state" of the species/elements present at surface.

If you want identify species for one or several elements in the sample High resolution narrow spectra are required for the interest elements.

The High resolution narrow spectra, allow you after fitting determine the area ratio in percent of the species present, without need to apply RSF.

After you know the percent of the species, you can apply these percent values to the AT% percent values obtained from the survey, allowing to know how many At.% percent of this emement corresponds to elemental state or oxide state for example.

Also of course is possible, quantify from the narrow spectra, drawing the baseline under the peak, but this procedure require acquire high resolution spectra of all elements detected in the survey including elements coming from contamination, or no relevant elements, making very long the experiment and increasing the X-Ray irradiation of the sample.

The CAsaXPS software developers have a document named "Understanding Relative Sensitivity Factors for Doublet Transitions", that can be useful to understand the process.

I attached this document available on internet in the Software Casa XPS site.

Good lock

Carmen

.

I totally agree with @Serra. Very comprehensive answer.

Christian Urban could you explain how to find the % of oxidation states of an element. What is the Sensitivity and related sensitivity factor.