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arXiv · 2606.13143

A first-principles approach for predicting infrared optical properties of solids

Sreerag Sundaram·Ziqi Guo·Dudong Feng·Karthik Sasihithlu·Xiulin Ruan
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Abstract

We present a simplified formalism for predicting infrared optical constants from first-principles calculations. Addressing limitations of the widely used four-parameter semi-quantum Lorentz model, the proposed approach bridges the gap between the harmonic three-parameter model and full self-energy-based methods. By incorporating essential anharmonic effects including four-phonon scattering and phonon renormalisation, the model provides an efficient and accurate alternative while maintaining low computational cost. The frequency-dependent refractive indices of MgO and rutile TiO$_2$ are computed and compared with experimental data, demonstrating good quantitative agreement. The framework offers a practical approach for predicting optical properties of materials across a wide range of materials.

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Sreerag Sundaram, Ziqi Guo, Dudong Feng, Karthik Sasihithlu, Xiulin Ruan. 2026-06-11. A first-principles approach for predicting infrared optical properties of solids. https://arxiv.org/abs/2606.13143

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