Objects Mixture Simulation Parameters <Prev Next>

Lineshape Function

This object is created under a Simulation object to allow an arbitrary function to be used as the lineshape applied to all transitions. For example, a the first derivative of a Gaussian lineshape could be modelled using:


The default lineshape function would be voigt(x,lor,gau). The function is held in the comment field for the object; in the constants window an enlarged text window replaces the normal comments window. See expressions for more details on the format of expressions. The function is normally evaluated out to WidthMult*(Lor+Gau+Width) from the line centre; the accuracy of the simulation will be controlled by WidthMult, nDF and SMargin settings in the Simulation object

Built In Variables

The following built in variables are available:

The distance from the line centre
The width parameter of the object.
The Lorentzian parameter from the toolbar and simulation object
The Gaussian parameter from the toolbar and simulation object.
Normally 0, but 1 if the overall line width is too small to convolute with, in which case the function is only evaluated at the line centre.


Active True if object is to be used
nDebug Set non zero to write information to the log window on each use


Width Used to determine how far from the line centre to extend the convolution. It can also be used as a parameter in the expression.