Hi, I do not actually see atoms that "after relaxation" go in positions that they did not occupy before relaxation. However, such effects can be absolutely "normal", in that due to periodicity, if you did not center your atomic positions around the middle of the cell along z direction, it can happen that an atom, let's say at z=0.0 at the beginning, after relaxation is found at z=-0.1 Ang. The visualization of the file with any visualization tool, will display the atoms in the primitive cell, so that atom will be seen at z = c - 0.1 Ang. Try to just replicate your cell twice along z and you'll see that the structure is correct.
By looking at the two files, also consider that: i) although the total final force is small, strictly speaking your calculation is not ended as far as relaxation is concerned (see the message "The maximum number of steps has been reached." at the end of the file) ii) you're forcing pw.x to compute every time nbnd=1186 bands. However, your system is composed of 1084 electrons that would correspond to 542 occupied bands for a semiconductor. For a metallic system, using occupation='smearing' automatically increases this value (542) by some percentage (something like 20%). You can see that also from the estimation of the Fermi level, 2.4851 eV, if compared with your highest occupied bands, just slightly below 20 eV. This implies that you're taking much more time than needed to converge scf cycles and atomic position optimization. I would get rid of the nbnd variable, complete the relaxation and only after that rerun the calculation with the optimized structure and a larger number of bands, in the case you really need them iii) I would check convergence against k-point grid, only one k-point could not be enough iv) you have specified dipfield = .true. from the documentation you read If .TRUE. and tefield==.TRUE. a dipole correction is also added to the bare ionic potential - implements the recipe of L. Bengtsson, PRB 59, 12301 (1999). See variables edir, emaxpos, eopreg for the form of the correction. Must be used ONLY in a slab geometry, for surface calculations, with the discontinuity FALLING IN THE EMPTY SPACE. So, I think that as you did, the variable is not effective. However, dipole correction for your slab geometry might be needed due to the asymmetry between the top and the bottom surface of the slab. Giovanni -- Giovanni Cantele, PhD CNR-SPIN c/o Dipartimento di Fisica Universita' di Napoli "Federico II" Complesso Universitario M. S. Angelo - Ed. 6 Via Cintia, I-80126, Napoli, Italy e-mail: [email protected] <[email protected]> Phone: +39 081 676910 Skype contact: giocan74 ResearcherID: http://www.researcherid.com/rid/A-1951-2009 Web page: https://sites.google.com/view/giovanni-cantele/home Il giorno gio 12 dic 2024 alle ore 06:18 Suraj P <[email protected]> ha scritto: > Dear QE users, > > I have relaxed a Pd-doped anatase TiO2 (001) supercell using Quantum > espresso. After relaxation, some atoms at the top surface of the slab is > going outside the cell. I have attached the input file and output file. > Kindly let me know why the atoms cross the boundaries of supercell. > > Input file: > https://drive.google.com/file/d/10-Q4xL-V3GD_gMzZ3ZJaiO2CrY7PZSsC/view?usp=sharing > Output file: > https://drive.google.com/file/d/17Nm9q5oiexxhtn16k4lkRdT43ZvnpLhi/view?usp=drive_link > > > Thanking you > Suraj > Research student > IIT Indian institute of technology > > _______________________________________________________________________________ > 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 >
_______________________________________________________________________________ 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
