Frost and coworkers, 2002, we can find the Raman and IR spectra of vivianite, baricite and bobierrite in their Figures and. The analysis of the Raman and IR spectra are reported in Table of their article. In the following Table , we consider only the Raman bands (cm -1 ), as in the Figure The instrument used by Frost and coworkers is a Renishaw 1000 Raman. The Raman spectra were excited by a He-Ne laser (633 nm). "Repeated acquisitions using the highest magnification were accumulated to improve the signal to noise ratio in the spectra". "Spectra at liquid nitrogen temperature were obtained using a Linkam thermal stage". "Band-component analysis was undertaken using the Jandel 'Peakfit' software package, … Band fitting was done using a Gauss-Lorentz cross-product function with the minimum number of component bands used to achieve a satisfactory fit. The Gauss-Lorentz ratio was maintained at values greater than 0.7". The Gauss-Lorentz cross product functions are not given in the article by in Origin Help we find an expression which is governed by parameter "s" as shape. Probably, the "ratio" in Frost et al. is the "shape" in Origin. In the Table given by Frost and coworkers, four bands are given, but in the Figure of the same article, the components used for fitting are five.