Dear QE users, I have obtained the HOMO and LUMO levels of a perovskite. It is an organic perovskite made up of slabs of I-Pb and an organic molecule wit C, S, O and N. The HOMO is on the I atoms and the LUMO in the S atoms, aproximately. The DOS show the last levels of the valence band in the I and the first levels of the conduction band in the molecule, which agrees with the previous results of the HOMO and LUMO levels.
However, the atoms with the highest intensities of I and S in the DOS are not those in which the HOMO and LUMO levels are. I expected to be the same, it is, the brightest atoms of I to be the same of the HOMO level and the DOS, and the brightest atoms of S to be the same of the LUMO level and the DOS, but it not so. I don't know how to explain this effect. Any suggestion? I have made the following calculations (input_dft=vdw-df-cx always): 1. A geometric optimization. This initial prediction of both unit-cell and atomic structure implements relaxations defined by calculations of both forces and stresses and was completed at a 2175 eV (160 Ry) kinetic-energy cutoff (and 640 Ry for the charge-density representation). 2. A self-consistent (scf, 4x4x4) calculation followed by a non-self-consistent (nscf, 8x8x8) calculation, achieving convergence with a kinetic-energy cutoff of 680 eV (50 Ry). 3. The extraction of the DOS, BS and electronic levels (HOMO, LUMO, ...) using the QE post-processing tools. Thank you very much for your help and Happy Christmas, David. -------------------------- David López Durán Lecturer/Associate Professor (non-tenure track) Department of Physics University of Córdoba, Spain Phone: +34 957 21 20 32 https://www.uco.es/organiza/departamentos/fisica/es/personal/personal-docente-e-investigador/149-david-lopez-duran https://es.linkedin.com/in/davidlopezduran _______________________________________________________________________________ The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare. -------------------------------------------------------------------------------- Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
