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arXiv · 2505.10041

QR$^2$-code: An open-source program for double resonance Raman spectra

Jianqi Huang·Renhui Liu·Ye Zhang·Nguyen Tuan Hung·Huaihong Guo·Riichiro Saito·Teng Yang
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Abstract

We present an open-source program, QR$^2$-code, that computes double-resonance Raman (DRR) spectra using first-principles calculations. QR$^2$-code can calculate not only two-phonon DRR spectra but also single-resonance Raman spectra and defect-induced DRR spectra. For defect-induced DDR spectra, we simply assume that the electron-defect matrix element of elastic scattering is a constant. Hands-on tutorials for graphene are given to show how to run QR$^2$-code for single-resonance, double-resonance, and defect-induced Raman spectra. We also compare the single-resonance Raman spectra by QR$^2$-code with that by QERaman code. In QR$^2$-code, the energy dispersions of electron and phonon are taken from Quantum ESPRESSO (QE) code, and the electron-phonon matrix element is obtained from the electron-phonon Wannier (EPW) code. All codes, examples, and scripts are available on the GitHub repository.

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Jianqi Huang, Renhui Liu, Ye Zhang, Nguyen Tuan Hung, Huaihong Guo, Riichiro Saito, Teng Yang. 2025-05-15. QR$^2$-code: An open-source program for double resonance Raman spectra. https://doi.org/10.1016/j.cpc.2025.110005

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