Dear Vikas You can also use the ab-initio implementation of vdW forces by switching on the input_dft="vdw-df" flag. HTH Giuseppe
On Tuesday 21 June 2011 16:40:02 Vikas Varshney wrote: > Dear All, > > I am trying to relax my WS2 unit cell structure using vc-relax (using PBE > pps) and I want to include disperson corrections to it. So, I tried using > the london flag = .true. However, on starting my job I got an error > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% >%%% from init_london : error # 1 > atom W not found > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% >%%% > > After going through mm_dispersion.f90, I found that the vdw_radius and c_6 > parameters are given for first 54 atoms only (which corresponds to first 5 > periods of periodic table). Tungsten (W), with atomic number of 74 is in > 6th period. > > I emailed Prof. Stefan Grimme (author of the references that are mentioned > in mm_dispersion.f90) if anything was further pursued. He replied > mentioning that they have approached this problem further and referred me > to his website, > > http://toc.uni-muenster.de/DFTD3/ > > and told me that this has already been implemented into major QM codes. > > Mentioning that, I have few questions. > 1. I wanted to ask if QE has incorporated the additions DFT-D, recently. > 2. Are there any other ways to incorporate dispersion interactions in > calculations in DFT. > > Currently, I am running my simulations on 4.2 version of the code that I > downloaded few months ago. I would high appreciate your insights in how > should I go about solving this problem regarding dispersion interactions in > Tungsten. > > Looking forward for a positive reply. > > Best Regards, > > Vikas Varshney, > Computational Materials Scientist, > Wright-Patterson Air Force Base, Dayton-OH (USA). -- ******************************************************** - 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>
