How to RSoXS

Abstract

Resonant Soft X-ray Scattering (RSoXS) has emerged as a powerful technique for investigating compositional and orientational heterogeneity in organic thin films. By exploiting the variation in optical constants near atomic absorption edges, RSoXS enables unprecedented contrast between organic materials and unique sensitivity to molecular orientation. Despite its growing importance over the past 15 years, particularly in organic electronics research, detailed guidance on proper implementation and analysis has been limited. This tutorial provides a comprehensive introduction to the technique, starting with the fundamental principles of near edge x-ray absorption fine structure spectroscopy and RSoXS contrast mechanisms. Using multi-walled carbon nanotubes as an illustrative example, we walk through best practices for sample preparation, measurement procedures, and data analysis. We present both model-free analysis approaches and detailed modeling using the open-source NIST RSoXS simulation suite. We intend this tutorial to serve as a practical resource for both new practitioners and experienced researchers, enabling quantitative analysis of molecular-scale structure in soft materials.