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FickDiffusionSQE¶
Description¶
This fitting function models the dynamic structure factor for a particle undergoing jump diffusion using Fick’s law for diffusion [1].
\[ \begin{align}\begin{aligned}S(Q,E) = Height \cdot \frac{1}{\pi} \frac{\Gamma}{\Gamma^2+(E-Centre)^2}\\\Gamma = DiffCoeff \cdot Q^{2}\end{aligned}\end{align} \]
where:
\(Height\) - Intensity scaling, a fit parameter
\(DiffCoeff\) - diffusion coefficient, a fit parameter
\(Centre\) - Centre of peak, a fit parameter
\(Q\) - Momentum transfer, an attribute (non-fitting)
Attributes (non-fitting parameters)¶
Name |
Type |
Default |
Description |
|---|---|---|---|
Q |
|||
WorkspaceIndex |
Properties (fitting parameters)¶
Name |
Default |
Description |
|---|---|---|
Height |
1.0 |
scaling factor |
Centre |
0.0 |
Shift along the X-axis |
DiffCoeff |
2.3 |
Diffusion coefficient (10^(-5)cm^2/s) |
References¶
Categories: FitFunctions | QuasiElastic
Source¶
C++ header: FickDiffusionSQE.h
C++ source: FickDiffusionSQE.cpp