2.2.1. Broad peak¶
Broad Lorentzian type peak on top of a power law decay
| Parameter | Description | Units | Default value |
|---|---|---|---|
| scale | Source intensity | None | 1 |
| background | Source background | cm-1 | 0 |
| porod_scale | Power law scale factor | None | 1e-05 |
| porod_exp | Exponent of power law | None | 3 |
| lorentz_scale | Scale factor for broad Lorentzian peak | None | 10 |
| lorentz_length | Lorentzian screening length | Å | 50 |
| peak_pos | Peak postion in q | Å-1 | 0.1 |
| lorentz_exp | exponent of Lorentz function | None | 2 |
The returned value is scaled to units of cm-1.
This model calculates an empirical functional form for SAS data characterized by a broad scattering peak. Many SAS spectra are characterized by a broad peak even though they are from amorphous soft materials. For example, soft systems that show a SAS peak include copolymers, polyelectrolytes, multiphase systems, layered structures, etc.
The d-spacing corresponding to the broad peak is a characteristic distance between the scattering inhomogeneities (such as in lamellar, cylindrical, or spherical morphologies, or for bicontinuous structures).
The returned value is scaled to units of cm-1, absolute scale.
2.2.1.1. Definition¶
The scattering intensity I(q) is calculated as
Here the peak position is related to the d-spacing as Q0 = 2|pi| / d0.
For 2D data: The 2D scattering intensity is calculated in the same way as 1D, where the q vector is defined as
Figure. 1D plot using the default values (w/200 data point).