I'm attempting to fit Cl2p XPS peak using casaXPS, where I expect it to exist in two different chemical states. Hence, the fitting includes a pair of doublets (total of four peaks). The constraints that one would naturally apply in this case are;
I was wondering whether the FWHM should be constrained to be equal for the doublet of the same chemical state?
Any information of a range of expected FWHM of Cl2p peaks is also appreciated.