On Tue, Jul 10, 2012 at 4:44 PM, Torstein Fjermestad < torstein.fjermestad at kjemi.uio.no> wrote:
> The problem is that I have so far only managed to complete step 1, to > compute the phonons. I am currently doing test calculations on a water > molecule and this is the input file of the phonon calculation: > > ... This calculation crashes presumably because it expects a file called > h2o.dynG0. But from where do I get this file? As far as I can see the > phonon calculation only produces the file h2o.dynG, not a h2o.dynG0 > file. > > Dear Torstein, the problem in your case is that q2r.x expects to find a phonon *dispersion* calculation, i.e. the phonon computed over a regular grid of q-points n reciprocal space. On the other hand, you only computed the phonons at Gamma. It is true that Gamma is just a 1x1x1 grid, and if you are sure it is enough to describe your system you can manage to convince q2r to use it. You need to do the following: 1. move h2o.dynG to h2o.dynG1 2. create a file called h2o.dynG0 which this inside: 1 1 1 1 0.0 0.0 0.0 3. try again with q2r.x Alternatively, you can just repeat the phonon calculation with ldisp = .true.; if you want your grid to be just the Gamma point you specify nq1=1, nq2=1, nq3=1. I stress that a single-point sampling may not be enough to describe accurately the properties of your system (unless the supercell is very large) but this you need to check for yourself. good work -- Lorenzo Paulatto IdR @ IMPMC/CNRS & Universit? Paris 6 phone: +33 (0)1 44275 084 / skype: paulatz www: http://www-int.impmc.upmc.fr/~paulatto/ mail: 23-24/4?16 Bo?te courrier 115, 4 place Jussieu 75252 Paris C?dex 05 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120710/fa55df1e/attachment-0001.htm
