A least-squares algorithm suitable for a small memory-size programmable desk calculator is proposed for smoothing and deconvoluting electron spectroscopy for chemical analysis spectra. Smoothing with quadratic polynomial passing through nine points is shown to be the most convenient. The same procedure is applied to compute derivatives of spectra; power and limitations of this extremely simple method are discussed, in relation to a reexamination of gold valence band spectra, revealing significant features.
Jean-Jacques Pireaux, "Smoothing and Resolution Enhancement of Photoelectron Spectra with the Aid of a Programmable Desk Calculator," Appl. Spectrosc. 30, 219-224 (1976)