# skued.potential_map¶

skued.potential_map(q, I, crystal, mesh)

Compute the electrostatic potential from powder diffraction data.

Parameters
• q (ndarray, shape (N,)) – Scattering vector norm ($$Å^{-1}$$).

• I (ndarray, shape (N,)) – Experimental diffracted intensity.

• crystal (crystals.Crystal) – Crystal that gave rise to diffraction pattern I.

• mesh (3-tuple ndarrays, ndim 2 or ndim 3) – Real-space mesh over which to calculate the scattering map. Format should be similar to the output of numpy.meshgrid.

Returns

out – Electrostatic potential computed over the mesh.

Return type

ndarray, ndim 2 or ndim 3

Raises

ValueError – if intensity data is not strictly positive.:

Notes

To compute the scattering map from a difference of intensities, note that scattering maps are linear in structure factor norm. Thus, to get the map of difference data I1 - I2:

$I = (\sqrt{I_1} - \sqrt{I_2})^2$

References

1

Otto et al., How optical excitation controls the structure and properties of vanadium dioxide. PNAS, vol. 116 issue 2, pp. 450-455 (2018). :DOI:10.1073/pnas.1808414115