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Updated: Dec 26, 2025
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Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
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Excited Electronic States in Total Isotropic Scattering from Molecules
Nikola Zotev1, Andrés Moreno Carrascosa1, Mats Simmermacher1
1EaStCHEM School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, U.K.
Journal of Chemical Theory and Computation
|March 7, 2020
Summary
We developed a new method to analyze ultrafast X-ray scattering data. This approach calculates isotropic scattering from electronic states, aiding in distinguishing molecular states and understanding scattering components.
Area of Science:
- Physical Chemistry
- Computational Chemistry
- Materials Science
Background:
- Ultrafast X-ray scattering is crucial for studying molecular dynamics.
- Analysis typically relies on the isotropic scattering component.
- Distinguishing electronic states and scattering contributions is challenging.
Purpose of the Study:
- To present an analytical method for calculating total isotropic scattering.
- To enable direct calculation from ab initio two-electron densities for ground and excited states.
- To generalize the method for elastic, inelastic, and mixed scattering components.
Main Methods:
- Development of an analytical method for total isotropic scattering calculation.
- Utilizing ab initio two-electron densities as input.
- Generalization to compute elastic, inelastic, and coherent mixed scattering.
Main Results:
- Demonstrated potential for differentiating between electronic states.
- Showcased decomposition of total scattering into elastic and inelastic components.
- Identified a constant scattering fingerprint from electron density redistribution in ammonia's excited state.
Conclusions:
- The new method provides insights into electronic state differentiation via X-ray scattering.
- Electron density changes significantly impact scattering, comparable to geometric changes.
- This analytical approach enhances the interpretation of ultrafast X-ray scattering experiments.
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