Direct integration and curve fitting techniques constitute the two main methods of peak area measurement. Simulated Ni 2p spectra are used to compare the effectiveness of the simple integral and linear background profiles for producing the correct peak areas. Although the simple integral profile shows more consistency and is to be preferred in general, certain fortuitous cancellation effects, particularly with nonmonochromatized spectra, make areas using the linear background fairly accurate in some instances. Curve fitting can overcome many of the problems of direct integration resulting from severe peak overlap. Two types of Gaussian/Lorentzian functions with a suitable exponential tailing function, which has a finite area over reasonable integration limits, are discussed with regard to their use in non-linear least-squares curve fitting methods. Also discussed is the usefulness of composite and difference spectra as simpler methods of determining the relative areas of overlapping peaks.", pages = "505-518", url = "http://www.ingentaconnect.com/content/sas/sas/1984/00000038/00000004/art00006", doi = "doi:10.1366/0003702844555205", keyword = "Computer algorithms, ESCA, Data analysis, Quantitative analysis" }