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Updated: Jan 24, 2026

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

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Efficient calculation of X-ray absorption spectra using Chebyshev-Slepian filter diagonalisation.

Simon P Neville¹, Michael S Schuurman¹

¹Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.

The Journal of Chemical Physics

|May 17, 2019

Summary

This study introduces Chebyshev-Slepian filter diagonalization, a novel computational method for simulating X-ray absorption spectra efficiently and accurately. It avoids calculating all core-excited states, simplifying spectral analysis.

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Area of Science:

Computational Chemistry
Quantum Chemistry
Spectroscopy

Background:

Simulating X-ray absorption spectra with ab initio electronic structure methods is computationally challenging.
Conventional methods require calculating numerous core-excited states, many of which are not spectroscopically relevant.

Purpose of the Study:

To develop a more efficient and user-friendly method for calculating X-ray absorption spectra.
To overcome the limitations of existing Chebyshev filter diagonalization techniques.

Main Methods:

Implementation of a time-independent Chebyshev filter diagonalization scheme.
Introduction of discrete prolate spheroidal sequences for filter construction, termed Chebyshev-Slepian filter diagonalization.
Application of the method at the second-order algebraic diagrammatic construction (ADC(2)) level of theory.

Main Results:

The Chebyshev-Slepian filter diagonalization method enables X-ray absorption spectra computation without explicit calculation of all core-excited eigenstates.
The new filters simplify the process, making filter diagonalization a "black-box" procedure.
Validation was performed by calculating the X-ray absorption spectra of trifluoroacetonitrile and 1,4-benzoquinone.

Conclusions:

Chebyshev-Slepian filter diagonalization offers an efficient and accurate approach for simulating X-ray absorption spectra.
This method reduces computational cost and user input compared to traditional techniques.
The approach is suitable for analyzing complex molecular systems.