Is it possible to extract information on elemental ratios from X-ray photoelectron spectroscopy (XPS)? For example, I am reading a paper and in it they say that the carbon to oxygen (C:O) ratios of the four samples are 2.8, 2.9, 5.1, and 23.3. However, the authors do not provide the actual XPS spectra, not even in a Supporting Information-type addendum.
I am a computational chemist and have no experience with XPS. I do know that elements, and even particular hybridizations, give characteristic peaks at characteristic binding energies (in units of eV, for example). This, I know, enables qualitative analysis of compounds. But is there a way to extract quantitative information from XPS? Suppose I want to determine the C:O ratio in a compound containing only C, O, and H. Do I take the ratio of the C and O peak heights, or do I take the ratio of the area under the peaks corresponding to C and O?
Do you know of any good review articles that would help me to understand the basics of XPS?