hi, i went through some textbooks about photoelectron spectroscopy and was looking for information on how it is used to determine the structure of a surface. but they mostly focus on how it can be used to identify the identity of the sample and some of the terms in the books were too technical for me to understand. so could someone explain to me why we can use photoelectron spectroscopy eg. XPS to determine the structure of a surface and what features in the spectrum do we have to take note of? thanks!!