X-ray scattering at the carbon absorption edge is uniquely sensitive to local molecular bond identity and orientation in organic nanostructures, encoded as a function of photon energy and polarization. However, quantitative analysis is precluded due to the lack of accurate optical models with bond and orientation specificity. We generate such a model through an algorithm that parameterizes and refines density functional theory calculations with angle-resolved absorbance spectroscopy measurements. The resulting optical tensor is shown to reproduce data from samples with domains of different orientation and crystalline packing, enabling label-free orientation analyses of individual chemical moieties within molecular nanostructures using resonant X-rays.
@article{arxiv.2509.01734,
title = {Quantitative and bond-traceable resonant X-ray optical tensors of organic molecules},
author = {Victor Murcia and Obaid Alqahtani and Harlan Heilman and Brian A. Collins},
journal= {arXiv preprint arXiv:2509.01734},
year = {2025}
}