ElasticDiffRotDiscreteCircle¶

Description¶

Summary¶

This fitting function models the elastic part of the dynamics structure factor of a particle undergoing discrete jumps on N-sites evenly distributed in a circle. The particle can only jump to neighboring sites. This is the most common type of discrete rotational diffusion in a circle.

$S(Q,E) \equiv = \int e^{-iEt/\hbar} I(Q,t) dt = A_0(Q,r) \delta (E)$

$A_0(Q,r) = \frac{1}{N} \sum_{k=1}^{N} j_0( 2 Q r sin(\frac{\pi k}{N}) )$

This function makes up the elastic part of DiffRotDiscreteCircle.

Attributes (non-fitting parameters)¶

Name	Type	Default	Description
N
Q
WorkspaceIndex

$N$ (integer, default=3) number of sites - $Q$ (double, default=0.5) Momentum transfer

Properties (fitting parameters)¶

Name	Default	Description
Height	1.0	Scaling factor to be applied to the resolution.
Centre	0.0	Shift along the x-axis to be applied to the resolution.
Radius	1.0	Circle radius [Angstroms]

Categories: FitFunctions | QuasiElastic

Source¶

C++ header: ElasticDiffRotDiscreteCircle.h (last modified: 2020-03-20)

C++ source: ElasticDiffRotDiscreteCircle.cpp (last modified: 2020-03-20)