Onion model: form factor of core-shell spheroid

Introduction

Spheroid is often used to model particle shapes in small-angle X-ray or neutron scattering modeling. If the particle consists of a core wrapped within a thin shell, one needs to adopt the core-shell spheroid model. Here we will generalize the simple core-shell model to a multi-layered model (onion model). This model can then be used to calculate SAXS or SANS intensities from spheroidal objects with radially continuous density profiles. The majority of this post can be found in the following paper:

Z. Jiang and W. Chen, Generalized skew-symmetric interfacial probability distribution in reflectivity and small-angle scattering analysis J. App. Cryst. 50, 1653-1663 (2017)