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# ElasticDiffRotDiscreteCircle¶

## 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.

1.0

Categories: FitFunctions | QuasiElastic