Search found 9 matches

by fdatchi
Mon Nov 19, 2012 6:25 pm
Forum: Response calculations
Topic: two phonon dos ?
Replies: 0
Views: 1251

two phonon dos ?

Hi, I'm reposting my question as a new topic in the hope of getting an answer. So here it goes: I made a complete RF calculation over the BZ and got the phonon DOS right with anaddb (version 6.12.1). I would like now to determine the two phonon dos sum/difference. As explained in the help page, I in...
by fdatchi
Thu Nov 08, 2012 5:40 pm
Forum: Response calculations
Topic: two phonon DOS [solved]
Replies: 4
Views: 1756

Re: two phonon DOS [solved]

Hi, I am also interested in getting the two phonon dos. I included the following code in anaddb: dossum 1 which I thought would produce a dossum output file as described in the help page, but got none. No output in the anaddb ouput file either. I could not find the input file mentionned by Igor (Act...
by fdatchi
Mon Sep 06, 2010 6:46 pm
Forum: Response calculations
Topic: problem with anaddb ?
Replies: 8
Views: 2859

Re: problem with anaddb ?

Another question: should I use the same number/grid of k-points as of q-points or these are completely unrelated ?

Frederic
by fdatchi
Mon Sep 06, 2010 3:52 pm
Forum: Response calculations
Topic: problem with anaddb ?
Replies: 8
Views: 2859

Re: problem with anaddb ?

Thanks matthieu.

Using a 8x8x8 grid adds a lot more q-points and thus as many more rf calculations.
Since the problem seems to be only for the Gamma-M branch, is it possible to only increase the number of q-points along this branch ?

Frederic
by fdatchi
Fri Aug 20, 2010 12:05 pm
Forum: Response calculations
Topic: symmetry of phonon modes
Replies: 13
Views: 7277

Re: symmetry of phonon modes

Thanks Igor, I could get the file. I understand from this tutorial that the list of character numbers are given in the same order as the list of symmetry operations given in the log file. I wonder why the symmetry operations are only given in the log file, in my opinion this is important enough info...
by fdatchi
Thu Aug 19, 2010 2:54 pm
Forum: Response calculations
Topic: symmetry of phonon modes
Replies: 13
Views: 7277

symmetry of phonon modes

Hi all, After reporting the eigendisplacements of phonon modes in the output of anaddb, there is an "Analysis of degeneracies and characters", where is listed the symmetry characters of each vibration mode in the form of a list of numbers as in the example below: Analysis of degeneracies a...
by fdatchi
Mon Aug 16, 2010 1:22 pm
Forum: Response calculations
Topic: problem with anaddb ?
Replies: 8
Views: 2859

Re: problem with anaddb ?

Thanls Matthieu. I tried with symdinmat 1, it did not change anything. I then tried to use decreasing values of rifcsph, it does affect the results below 20 Bohr but does not help to recover the correct behavior along Gamma-M and introduces more negative values. Could you indicate how to generate a ...
by fdatchi
Tue Jul 27, 2010 11:35 am
Forum: Response calculations
Topic: problem with anaddb ?
Replies: 8
Views: 2859

Re: problem with anaddb ?

Hi,
Thanks for your suggestion. I m out of office at present, I will try it out as soon as I come back.
Frederic
by fdatchi
Wed Jul 21, 2010 4:12 pm
Forum: Response calculations
Topic: problem with anaddb ?
Replies: 8
Views: 2859

problem with anaddb ?

Hi all, I've been using ABINIT v5.8.4 to calculate the properties of a high pressure phase of CO2, space group P42/mnm. I first optimized the strucutre (cell paramaters + atomic positions) for a given stress target then I ran a response function calculation to get the phonon dispersion in the IBZ, f...