The parameter m specifies the width of the Gaussian used to convolute the Lorentzian curve. LA(α, β, m) = Asymmetric line-shape where α and β define the spread of the tail on either side of the Lorentzian component.
Parameters a and b change the shape of the asymmetry while n defines the width of the Gaussian component used to convolute the shape of the profile. Ī(a,b,n)GL(p) = Gaussian/Lorentzian product modified by an asymmetric form. The K(alpha) X-ray source line-shape is also Lorentzian in shape. Note: The contribution of the spectrometer is Gaussian in shape while the natural core level line-shape is Lorentzian (with a small degree of tailing or asymmetry to higher binding energy).
SGL(p) = Gaussian/Lorentzian sum formula where the mixing is determined by m = p/100, SGL(100) is a pure Lorentzian while SGL(0) is pure Gaussian. GL(p) = Gaussian/Lorentzian product formula where the mixing is determined by m = p/100, GL(100) is a pure Lorentzian while GL(0) is pure Gaussian. Some common line-shape definitions used in CasaXPS are:
