$\renewcommand\AA{\unicode{x212B}}$

ElasticDiffSphere¶

Description¶

This fitting function models the elastic part of the dynamics structure factor of a particle undergoing continuous diffusion but confined to a spherical volume, ElasticDiffSphere.

$S(Q,E\equiv \hbar \omega) = (3 \frac{j_1(QR)}{QR})^2(Q\cdot R) \delta (\omega)$

Because of the spherical symmetry of the problem, the structure factor is expressed in terms of the $j_l(z)$ spherical Bessel functions.

Attributes (non-fitting parameters)¶

Name	Type	Default	Description
Q
WorkspaceIndex

$Q$ (double, default=1.0) 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	2.0	Sphere radius

Categories: FitFunctions | QuasiElastic

Source¶

C++ header: ElasticDiffSphere.h

C++ source: ElasticDiffSphere.cpp