On 12 November 2012 05:46, Elias Albert <physics-passion at live.com> wrote:
> Dear all, > > I am doing some phonon calculations for an 8 atom supercell at q=0. I have > therefore got 24 irreducible representations.. These representations are > all of A symmetry. > > (1) Is there a possibility to calculate the phonon frequencies for each > representation on its own (as I am interested in checking the value of > first frequency) or does the code calculate all 24 representations in one > go ? > > The frequencies are the (square root divided by some mass of the) eigenvalues of the dynamical matrix: you need all the matrix before diagonalizing it > (2) Is there a way that the code just calculates the dynamical matrices > WITHOUT diagnalizing them? and then use dynmat.x to do the diagonalization? > If this is possible, does it reduce computation time? > ph.x computes the dynamical matrix and store it in the fildyn files, then it also diagonalize it, but you can ignore this part if you wish. > > Thanks > bests -- Dr. 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://pwscf.org/pipermail/pw_forum/attachments/20121112/9ece43d3/attachment.html