Dear vicky singh I've done more than few calculations with that same Co pseudopotential. Your wavefunction cutoff is far too low. I used 35/280 Ry. Which kind of cell optimisation have you performed? Have you tried vc-relax with bfgs? What about nspin=2? As you know, Co is a ferromagnetic metal... However, your calculated parameters do not seem so bad to me. Hope this help
Giuseppe On Friday 17 December 2010 06:57:01 you wrote: > Hi > I am extremly sorry to attach wrong code for Co. Kindly ignore it. I am > attaching the correct code. > > vicky singh > > On Fri, Dec 17, 2010 at 11:09 AM, vicky singh <kirtinandan07 at gmail.com>wrote: > > Hi > > I am trying to determine the lattice parameter of hcp Co. The reported > > experimental results is a = 4.74 bohr c/a = 1.62 but i am getting a = > > 4.675 and c/a = 1.58 . I am using the GGA PP Co.pbe-nd-rrkjus.UPF which > > is expected to overestimate the lattice parameter as compared to LDA PP > > but here it is underestimating the lattice parameter by around 2%. am i > > doing any thing wrong or this value i should proceed with this result for > > my further calculation. I am attaching the input file and the plot of E > > vs lattice parameter. > > > > Please help. Thanks in advance. > > > > vicky singh > > research student > > Bangalore -- ******************************************************** - Article premier - Les hommes naissent et demeurent libres et ?gaux en droits. Les distinctions sociales ne peuvent ?tre fond?es que sur l'utilit? commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la libert?, la propri?t?, la s?ret? et la r?sistance ? l'oppression. ******************************************************** ? ?Giuseppe Mattioli ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?CNR - ISTITUTO DI STRUTTURA DELLA MATERIA ? ? ?v. Salaria Km 29,300 - C.P. 10 ? ? ? ? ? ? ? ? ? ?I 00015 - Monterotondo Stazione (RM) ? ? ? ? ? ? ?Tel + 39 06 90672836 - Fax +39 06 90672316 ? ? ? ?E-mail: <giuseppe.mattioli at ism.cnr.it>
