28.1.31 ECS

Function

y=y_0+\frac A{w\sqrt{2\pi }}\{e^{-0.5z^2}\left( 1+\frac{a_3}{3!}z(z^2-3)+\frac{a_4}{4!}(z^4-6z^3+3)+\frac{10a_3^2}{6!}(z^6-15z^4+45z^2-15)\right) \}

where z=\frac{x-x_c}w

Brief Description

Edgeworth-Cramer Peak Function for use in chromatography.

Sample Curve

ECS.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: A > 0.0, w > 0.0

Upper Bounds: none

Script Access

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

Function File

FITFUNC\EDGWTHCR.FDF

Category

Peak Functions, PFW, Chromatography