Please check this http://www.democritos.it/pipermail/pw_forum/2005-April/002408.html
On Fri, May 4, 2012 at 2:26 PM, Iyad AL-QASIR <iyad.ne at gmail.com> wrote: > Dear All, > I am trying to understand the format of the force constant file (*.fc) > generated by running the executable q2r.x > > I hope someone could answer (or comment on) my questions below. > > Below is the part of q2r.f90 that prints force constants to *.fc > > ?DO j1=1,3 > ??????? DO j2=1,3 > ?????????? DO na1=1,nat > ????????????? DO na2=1,nat > ???????????????? WRITE (2,'(4i4)') j1,j2,na1,na2 > ???????????????? nn=0 > ???????????????? DO m3=1,nr3 > ??????????????????? DO m2=1,nr2 > ?????????????????????? DO m1=1,nr1 > ????????????????????????? nn=nn+1 > ????????????????????????? WRITE (2,'(3i4,2x,1pe18.11)')?? & > ?????????????????????????????? m1,m2,m3, > DBLE(phid(nn,j1,j2,na1,na2))???????????? ! why nn not > ?????????????????????? END DO > ??????????????????? END DO > ???????????????? END DO > ????????????? END DO > ?????????? END DO > ??????? END DO > ???? END DO > > Here are my notes and questions: > 1- j1 and j2 stands for x, y, and z directions? > 2- m1, m2, and m3 represents the integers for the position vector of a given > unitcell? > 3- Why in phid(nn, j1,j2,na1, na2) m1, m2 and m3 are mapped into nn? Where > nn=m1*m2*m3 > 4- How can I build from the? *.fc file a square force constants matrix where > each element is 3x3. That is, to build the conventional matrix we see in > text books? > > Thank you very much, > IYAD Al-Qasir > > X-ray and Neutron Scattering and Spectroscopy Group > Materials Science and Technology Division > ORNL > > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Dhruv
