.. _func-Voigt: ===== Voigt ===== .. index:: Voigt Description ----------- A Voigt function is a convolution between a Lorentzian and Gaussian and is defined as: .. math:: V(X,Y) = \frac{Y}{\pi}\int_{-\infty}^{+\infty}dz\frac{\exp^{-z^2}}{Y^2 + (X - z)^2}, where - X - Normalized line separation width; - Y - Normalized collision separation width. Generally, the Voigt function involves a numerical integral and is therefore a computational intensive task. However, several approximations to the Voigt function exist making it palatable for fitting in a least-squares algorithm. The approximation used here is described in - A.B. McLean, C.E.J. Mitchell, and D.M. Swanston. *Implementation of an Efficient Analytical Approximation to the Voigt Function for Photoemission Lineshape Analysis.* Journal of Electron Spectroscopy and Related Phenomena **69.2** (1994): 125–132 `doi:10.1016/0368-2048(94)02189-7 `__ The approximation uses a combination of 4 Lorentzians in two variables to generate good approximation to the true function. .. attributes:: .. properties:: .. categories:: .. sourcelink::