An exciting approach to theoretical spectroscopy

Martí Raya-Moreno; Alexander Buccheri; Noah Alexy Dasch; Nasrin Farahani; Ignacio Gonzalez Oliva; Andris Gulans; Manoar Hossain; Hannah Kleine; Martin Kuban; Sven Lubeck; Benedikt Maurer; Pasquale Pavone; Fabian Peschel; Daria Popova-Gorelova; Lu Qiao; Elias Richter; Santiago Rigamonti; Ronaldo Rodrigues Pela; Maximilian Schebek; Kshitij Sinha; Daniel T. Speckhard; Jan Stutz; Sebastian Tillack; Dmitry Tumakov; Seokhyun Hong; Jānis Užulis; Mara Voiculescu; Cecilia Vona; Mao Yang; Claudia Draxl

arXiv · 2601.11388

An exciting approach to theoretical spectroscopy

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Abstract

Theoretical spectroscopy, and more generally, electronic-structure theory, are powerful concepts for describing the complex many-body interactions in materials. They comprise a variety of methods that can capture all aspects, from ground-state properties to lattice excitations to different types of light-matter interaction, including time-resolved variants. Modern electronic-structure codes implement either a few or several of these methods. Among them, exciting is an all-electron full-potential package that has a very rich portfolio of all levels of theory, with a particular focus on excitations. It implements the linearized augmented planewave plus local orbital (LAPW+LO) basis, which is known as the gold standard for solving the Kohn-Sham equations of density-functional theory (DFT). Based on this, it also offers benchmark-quality results for a wide range of excited-state methods. In this review, we provide a comprehensive overview of the features implemented in exciting in recent years, accompanied by short summaries on the state of the art of the underlying methodologies. They comprise DFT and time-dependent DFT (TDDFT), density-functional perturbation theory (DFPT) for phonons and electron-phonon coupling, and many-body perturbation theory in terms of the $GW$ approach and the Bethe-Salpeter equation (BSE). Moreover, exciting can handle resonant inelastic x-ray scattering (RIXS), pump-probe spectroscopy as well as exciton-phonon coupling (EXPC). Finally, we cover workflows and a view on data and machine learning (ML). All aspects are demonstrated with examples for scientifically relevant materials.

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Martí Raya-Moreno, Alexander Buccheri, Noah Alexy Dasch, Nasrin Farahani, Ignacio Gonzalez Oliva, Andris Gulans, Manoar Hossain, Hannah Kleine, Martin Kuban, Sven Lubeck, Benedikt Maurer, Pasquale Pavone, Fabian Peschel, Daria Popova-Gorelova, Lu Qiao, Elias Richter, Santiago Rigamonti, Ronaldo Rodrigues Pela, Maximilian Schebek, Kshitij Sinha, Daniel T. Speckhard, Jan Stutz, Sebastian Tillack, Dmitry Tumakov, Seokhyun Hong, Jānis Užulis, Mara Voiculescu, Cecilia Vona, Mao Yang, Claudia Draxl. 2026-01-16. An exciting approach to theoretical spectroscopy. https://arxiv.org/abs/2601.11388

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