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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