How to Calculate Cohesive Energy using Quantum Espresso? [TUTORIAL]
In this hands-on Quantum ESPRESSO tutorial, I walkthrough the process of calculating the cohesive energy (per atom) of a crystal, using Silicon as an example.
The formula for the cohesive energy (per atom) is
E_\mathrm{coh/atom}=-(E_\text{bulk(per atom)}-E_\text{isolated atom})
The input and output files form the tutorial are available here: https://www.bragitoff.com/wp-content/...
The CIF file for the Silicon crystal used in this tutorial is available here: https://www.bragitoff.com/wp-content/...
I used the material mp-149 from materialsproject.org to obtain the CIF file: https://next-gen.materialsproject.org...
Unit conversion web app: https://ripertools.turbomole.org/
The reference value of 4.63 eV/atom for the cohesive energy of the Silicon crystal was obtained form this paper: https://journals.aps.org/prb/pdf/10.1...
The most crucial part of the cohesive energy calculation is the calculation of isolated atom's ground state energy as it requires the knowledge and correct treatment of the electron configuration by doing spin-polarized calculation (nspin = 2).
The electron configuration of Silicon is [Ne] 3s² 3p².