# Scattering
Function package for generating theoretical light scattering models. Composed during the 2021 CHARM REU Program for the Furst Group.
## Usage
The functions mie_scattering and rayleigh_scattering calculate theoretical light scattering properties, including scattering intensities and photon mean-free path. Inputs are the system parameters (particle and medium refractive indeces, particle radii, incident light wavelength) along with the desired structure factor model (default S(q)=1). See the documentation within scattering.py for further detail. Examples are given below and example scripts can be found in the "Examples" folder.
## Examples
In the simplest case, only the following system parameters meed to be input:
* particle refractive index, n_p
* medium refractive index, n_s
* particle radii, a_p
* wavelength of the incident light in a vacuum, lambda_vac
* particle volume fraction, phi
```python
theta, i1, i2, l_star, stats = mie_scattering(n_p, n_s, a_p, lambda_vac, phi)
```
Plotting i1 and i2 versus theta generated the polar plots seen above.
To specify the structure factor, the argument "struct" can be used. Currently implimented is a Percus-Yevick hard sphere structure factor ('PY'), a hard sphere with an excluded annulus ('PYAnnulus'), and a sticky hard sphere model with a square potential well ('SHS'). For some models, additional parameters must be specified using the "optional_params" arguement. Examples of each are seen below along with an plot of example parameters. See the documentation of scattering.py for parameter details and citations.
```python
_, _, _, _, [q, _, s_q, _, _, _, _, _] = mie_scattering(n_p, n_s, a_p, lambda_vac, phi, struct='PY')
... = mie_scattering(n_p, n_s, a_p, lambda_vac, phi, sruct='PYAnnulus', optional_params=[1.2*a_p])
... = mie_scattering(n_p, n_s, a_p, lambda_vac, phi, sruct='SHS', optional_params=[0.2, 0.05])
```
%20Models.png)