VoigtPeak
VoigtPeak (w, x)
The VoigtPeak function returns a value from a Voigt peak shape defined by coefficients in wave w at location x. It was added in Igor Pro 8.00.
The Voigt peak shape is defined as a convolution of a Gaussian and a Lorenztian peak. We use an approximation that is described by the author as having "accuracy typically at least 13 significant digits". This function is equivalent to the built-in Voigt fitting function. See Built-in Curve Fitting Functions.
The coefficients are:
| w[0]: | Vertical offset. | |
| w[1]: | Peak area. | |
| w[2]: | Peak center location. | |
| w[3]: | Gaussian component width expressed as Full Width at Half Max (FWHM). | |
| w[4]: | Ratio of Lorenztian component width to the Gaussian component width. For w[4]=0, the peak shape is purely Gaussian, as w[4] → ∞, the peak shape become purely Lorenztian. A value of 1 results in Gaussian and Lorenztian components of equal width. | |
References
The code used to compute VoigtPeak was written by Steven G. Johnson of MIT. You can learn more about it at http://ab-initio.mit.edu/Faddeeva.