ScatteringFitComponentXTables#

class pyxem.components.ScatteringFitComponentXTables(elements, fracs, N=1.0, C=0.0)[source]#

Bases: Component

A scattering component to fit background atomic scattering. Calculates the sum of the squares sum_squares = sum (ci * fi**2 ) and the square of the sum square_sum = (sum(ci * fi))**2 for atomic fraction ci with electron scattering factor fi. The latter is used for normalisation.

N and C are fitting parameters for the Component class.

The fitted function f is of the form:

f = sum(fi), fi = ai * exp(-bi*g^2) where 1 < i < 5, ai, and bi are tabulated constants, and g = 1/d = 2sin(theta)/lambda is the scattering vector magnitude. The factors are tabulated in ATOMIC_SCATTERING_PARAMS_XTABLES.

The fitted scattering factor is from [1].

Parameters:

  • elements (list of str) – A list of elements present (by symbol).

  • fracs (list of float) – A list of fraction of the respective elements. Should sum to 1.

  • N (float) – The “slope” of the fit.

  • C (float) – An additive constant to the fit.

References

[1] Prince, E. (2004). International tables for crystallography. Vol. C, table 4.3.2.3.

Attributes

ScatteringFitComponentXTables.trait_added

An event fired when a new trait is dynamically added to the object.

ScatteringFitComponentXTables.trait_modified

An event that can be fired to indicate that the state of the object has been modified.

Methods

ScatteringFitComponentXTables.function(x)

The actual fitted function.