Dear Vishva, before running any calculation it is a good practice to visualize your input structure, because many times convergence issues derive from errors in the input geometry.
If you do so with yours, you see atoms at extremely small distances from each other, which prevents pw.x from reasonably converging in an acceptable number of steps. The second step is to understand why the structure is wrong. In your case my guess is that you tell pw.x that you're providing positions in alat units, whereas those units are Angstrom. The number of atoms depends on what you want to do. If you what to use a simple cubic unit cell (as in your input file) and the bcc unit cell is composed by N atoms, then the 1x1x1 CONVENTIONAL unit cell will contain 2N atoms. If, on top of that, you want also build a 2x2x2 unit cell, than that number has to be multiplied by 2x2x2. Giovanmi -- 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 lun 13 mag 2024 alle ore 12:08 VISHVA JEET ANAND via users < [email protected]> ha scritto: > Dear Users > I try to run Fe (bcc) structure 2x2x2 supercell for relaxation > calculation but scf does not converge in 1000 iterations. Secondally how > many no. of atoms in Fe (bcc) structure. Here I attached my input file. > > -- > With Regards > Vishva Jeet Anand > Research Scholar > Department of Chemistry > > _______________________________________________ > 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
