28.1.75 GCAS

Function

f\left( z\right)  =y_0+\frac A{w\sqrt{2\pi }}e^{\frac{-z^2}2}\left( 1+|\sum_{i=3}^4\frac{a_i}{i!}H_i\left( z\right)| \right)

z=\frac{x-x_c}w

H_3=z^3-3z

H_4=z^4-6z^3+3

Brief Description

Gram-Charlier peak function for use in chromatography.

Sample Curve

GCAS.png

Parameters

Number: 6

Names: y0, xc, A, w, a3, a4

Meanings: y0 = offset, xc = center, A=area, w=half width, a3 = unknown, a4 = unknown

Lower Bounds: w > 0.0

Upper Bounds: none

Script Access

nlf_gcas(x,y0,xc,A,w,a3,a4)

Function File

FITFUNC\GRMCHARL.FDF

Category

Peak Functions, PFW, Chromatography