Electric field response in FHI-aims using DFPT

Prepared by Connor L. Box, James A. Green, Reinhard J. Maurer and Mariana Rossi

This is a tutorial for calculating the response of molecules and crystals to an external homogenous electric field using density functional perturbation theory (DFPT) as implemented in FHI-aims. Specifically, we are going to be calculating the IR and Raman spectra of i) a benzene molecule and ii) a benzene crystal.

Part i) of the tutorial was used in the FHI-aims webinar Advanced Electronic Structure Methods for Battery Design and Vibrational Spectroscopy 30 January 2025.

Input files and solutions are available within this repo, in each specific Tutorial directory.

Summary of the tutorial

The tutorial is organised as follows:

Part 1 introduces density functional perturbation theory and response to electric fields.
Part 2 simulates the IR and Raman spectra of benzene using DFPT
Part 3 simulates the IR and Raman spectra of a benzene crystal using DFPT