[Pw_forum] propagation direction of LO-TO splitting for dynmat.in file phonon calculation
stefano de gironcoli
degironc at sissa.it
Sun Dec 25 08:02:03 CET 2016
Dear Wei Li,
from the header of the dynmat.f90 source code
!
! This program
! - reads a dynamical matrix file produced by the phonon code
! - adds the nonanalytical part (if Z* and epsilon are read from file),
! applies the chosen Acoustic Sum Rule (if q=0)
! - diagonalise the dynamical matrix
! - calculates IR and Raman cross sections (if Z* and Raman tensors
! are read from file, respectively)
! - writes the results to files, both for inspection and for plotting
!
! Input data (namelist "input")
!
! fildyn character input file containing the dynamical matrix
! (default: fildyn='matdyn')
! q(3) real calculate LO modes (add nonanalytic terms) along
! the direction q (cartesian axis, default: q=(0,0,0) )
the value of the vector q (when different from zero) is interpreted as
the direction of propagation of the phonons.
stefano
On 25/12/2016 02:20, Wei Li wrote:
>
> Hi Friends,
>
> I plan to calculate the infrared spectrum of anatase TiO2 bulk using
> pw.x (scf), ph.x calculates phonon frequencies and effective charge
> etc.. Then the dynmat.x is used to calculate LO-TO splitting.
>
> The ph.x calculation is performed at single q, i.e., q=0.0,0.0,0.0 in
> ph.in <http://ph.in> file
>
>
> The question is how to define the
>
> propagation direction of LO-TO splitting, q(i), i=1,2,3, in the
> dynmat.in <http://dynmat.in> file?
>
> For instance, how to set q(1),q(2),q(3)?
>
>
>
>
>
>
> --
> *Wei Li*
> PhD student
> State Key Lab of Theoretical & Computational Chemistry
> Institute of Theoretical Chemistry
> Jilin University
> Changchun, 130023
> P.R. China
> Email: liwei0099 at gmail.com <mailto:liwei0099 at gmail.com>
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
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