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:
x/Width*exp(-sqr(x/Width))
The default lineshape function would be voigt(x,wLor,wGau). 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*(wLor+wGau+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:
x
|
The distance from the line centre
|
Width
| The width parameter of the object.
|
wLor
|
The Lorentzian parameter from the toolbar and simulation object Note that this is Lor in versions before 10.1.145, when it was renamed to avoid confusion with the lor() function.
|
wGau
| The Gaussian parameter from the toolbar and simulation object. Note that this is Gau in versions before 10.1.145, when it was renamed to avoid confusion with the gau() function. |
Stick
| 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.
|
Settings
Active |
True if object is to be used |
nDebug |
Set non zero to write information to the log window on
each use |
Parameters
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.
|