lorentz

Ornstein-Zernicke correlation length model

Parameter	Description	Units	Default value
scale	Scale factor or Volume fraction	None	1
background	Source background	cm-1	0.001
cor_length	Screening length	Å	50

The returned value is scaled to units of cm^-1 sr^-1, absolute scale.

Lorentz (Ornstein-Zernicke Model)

Definition

The Ornstein-Zernicke model is defined by

$$I(q)=\frac{\text{scale}}{1+(qL)^2}+\text{background}$$

The parameter $L$ is the screening length cor_length.

For 2D data the scattering intensity is calculated in the same way as 1D, where the $q$ vector is defined as

$$q=\sqrt{q_x^2 + q_y^2}$$

Fig. 106 1D plot corresponding to the default parameters of the model.

Source

lorentz.py

References

1. L.S. Qrnstein and F. Zernike, Proc. Acad. Sci. Amsterdam 17, 793 (1914), and Z. Phys. 19, 134 (1918), and 27, 761 {1926); referred to as QZ.

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