Dear Saiyed, when convergence issues show up there are several tricks you might consider, one of these is certainly reducing mixing_beta, another could be increasing degauss.
However, before trying any trick to cure a calculation particularly difficult to converge, as a rule of thumb the first step is to check your input file parameters including cut-off, k-point grid, degauss, GEOMETRY, pseudopotentials, etc. After a quick look to your input file I can notice: - an incredibly huge value of degauss (1d-1 Ry = 0.1 Ry = 1.36 eV, this would smear even the band gap of silicon I think) - a mixing beta of 0.6, actually the advise of reducing it in cases of difficult convergence is meant to go down to even 0.1 or 0.05 - but MOST IMPORTANTLY you specify ATOMIC_POSITIONS in crystal units, that are usually expected to be numbers in the range [-1,1] because in units of the lattice vectors there should be no reason to specify the position of an atom in a unit cell far apart from the origin. On the other hand, the numbers in your input file seem to indicate that you're actually giving the positions in Angstrom, because they are huge. If you try to visualize your input file using, for example XCrysDen, you can easily see atoms at incredibly huge distances. The geometry becomes much more reasonables if you replace "crystal" with angstrom. After doing that, recheck the geometry (with XCrysDen) to understand if it is what you expect or if there are still issues, before running any calculation. 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 mer 28 feb 2024 alle ore 08:41 Saiyed Tasnim Md Fahim < [email protected]> ha scritto: > Dear users, > I am working with calcite in Quantum Espresso 7.1. I want to perform a > vc-relax calculation for 3 layers of calcite but after 100 iterations > convergence is not achieved. I changed the mixing beta but it did not work. > > I have attached the input file with this mail. Kindly let me know how I > should proceed for both the convergence. > > Sincerely, > Saiyed Tasnim Md Fahim, > Ph.D. Student, > Environmental Engineering, > University of Southern California. > _______________________________________________ > The Quantum ESPRESSO community stands by the Ukrainian > people and expresses its concerns about the devastating > effects that the Russian military offensive has on their > country and on the free and peaceful scientific, cultural, > and economic cooperation amongst peoples > _______________________________________________ > 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 community stands by the Ukrainian people and expresses its concerns about the devastating effects that the Russian military offensive has on their country and on the free and peaceful scientific, cultural, and economic cooperation amongst peoples _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
