Dear Anthony "band" or "nscf" calculations do not work in the case of hybrid calculations. You can find the reason here:
yourQE/PW/examples/EXX_example/README There is no simple workaround. You can only struggle to draw a band structure by using the largest number of scf k-points affordable by your PBE0 calculation... HTH Giuseppe On Monday 15 October 2012 22:49:19 Anthony Ruth wrote: > Hello, I am trying to use version 5.0.0 to generate the band structure of a > photocathode. To do so I have been using 'vc-relax' to find the optimized > structure, copied the resulting structure to a new input file and used > 'scf' to record the bands in the scratch directory, using 'bands' to print > the bands along certain points in k space, and finally using some > post-precessing to plot it all. > > This method has worked correctly for my first run using the default > potential with scf which is PBE. However since this is a photocathode the > band gap is critically important, and my adviser recommended to use PBE0 > which is supposed to more accurately predict the band gaps. So I took the > optimized crystal structure and used it to run an scf calculation with > input_dft="PBE0". The scf calculation seemed to work correctly, but when I > run the band calculation I get an error that says: ef not found in file. I > compared the scratch directories of the calculation using PBE and the > calculation using PBE0 and discovered that there were 4 files that were > present in the PBE scratch directory that were not present in the PBE0 > directory. Two of the four files appeared to be copies of the > pseudopotentials, but the other two were data_file.xml and gvectors.dat. I > examined the data_file.xml for awhile and found that it contained the fermi > energy among many other things. gvectors.dat appears to be a byte stream, > so there is no way for me to interpret its contents. > > I copied the data_file.xml from the PBE scratch directory to the PBE0 > scratch directory and reran the 'bands' calculation. Lo and behold, the > calculation made it past the place that it complained about not finding the > fermi energy previously, however it could not converge during the > self-consistent calculations; probably because it was using some incorrect > settings. Also it mentioned not being able to locate a restart file; maybe > that is what gvectors.dat is for? > > What I would like to know is: is this a bug? It seems to me that these > other files should have been created when using scf with PBE0, but they > just weren't. Is there a way to force these files to be created? Is it > worthwhile to try to look through the data_file.xml and make the changes > necessary to run this calculation? I noticed two pieces of information that > are incorrect in the results file because it used information from PBE > instead of PBE0, but there might be many more differences that I don't see. > > -Anthony Ruth > Research Assistant at Argonne using NERSC computers. -- ******************************************************** - 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>
