A large percentage of the problems reported to the mailing list are caused by incorrect input data. Before reporting a problem with strange crashes or strange results, please have a look at your structure with XCrySDen. XCrySDen can directly visualize the structure from both PWscf input data:
xcrysden --pwi "input-data-file"and from PWscf output as well:
xcrysden --pwo "output-file".Unlike most other visualizers, XCrySDen is periodicity-aware: you can easily visualize periodically repeated cells. You are advised to always use XCrySDen to check your input data!
The following site contains a lot of crystal structures:
http://cst-www.nrl.navy.mil/lattice.
"Since this seems to come up often, I'd like to point out that the
American Mineralogist Crystal Structure Database
(http://rruff.geo.arizona.edu/AMS/amcsd)
is another excellent place to
find structures, though you will have to use it in conjunction with
the Bilbao crystallography server (http://www.cryst.ehu.es),
and have some understanding of space groups and Wyckoff positions".
See also:
http://cci.lbl.gov/cctbx/index.html.
There are several different way to specify structures, described in detail in Doc/INPUT_PW.*.
If you need to create a supercell and are too lazy to create a small program to translate atoms, you can
"You might find this web site useful: http://www.cryst.ehu.es/cryst/get_kvec.html" (info by Cyrille Barreteau, nov. 2007). Or else: in textbooks, such as e.g. The mathematical theory of symmetry in solids by Bradley and Cracknell.
Auxiliary code kpoints.x, found in pwtools/ and produced by make tools, generates uniform grids of k-points that are equivalent to Monkhorst-Pack grids.