On 16/04/2014 11:29, Zarah Baiyee wrote: > Dear all, > > I am studying a BaFeO3 perovskite structure, and I am struggling with > the convergence, primarily the Ecut WFC convergence. > > So far I have used a variety of PPs for this structure, yet cannot get a > sensible convergence for the Ecut Wfc, please see my convergence data > below:
Dear Zarah, 1) you do not check cutoff convergence on the total energy, but on its derivtives: forces for a distorted configuration, lattice parameters, bulk moduli... E.g. you want an eq. lattice parameter converged to better than .1 a.u, a bulk modulus converged to better than 3-4%, and phonons converged to better than 1%. 2) for pseudopotentials, the defaults you should probably use are the http://qe-forge.org/gf/project/pslibrary/ (we keep a compiled version of all the pseudos here http://theossrv1.epfl.ch/Main/Pseudopotentials) or the GBRV high-throghput library http://www.physics.rutgers.edu/gbrv/ (just be careful that this latter might have elements with very large numbers of semicore electrons - listed here in a very cool manner: http://theospc12.epfl.ch/GBRV_map/css3d_periodictable_GBRV.html ) nicola ---------------------------------------------------------------------- Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
