# Input File Description ## Program: matdyn.x / PHonon / Quantum ESPRESSO (version: 6.7GPU)
> > ### TABLE OF CONTENTS INTRODUCTION &INPUT flfrc | asr | dos | nk1 | nk2 | nk3 | deltaE | ndos | degauss | fldos | flfrq | flvec | fleig | fldyn | at | l1 | l2 | l3 | ntyp | amass | readtau | fltau | la2F | q_in_band_form | q_in_cryst_coord | eigen_similarity | fd | na_ifc | nosym | loto_2d | loto_disable AtomicPositionSpecs X | Y | Z | ityp qPointsSpecs nq | q_x | q_y | q_z | nptq qPointsSpecs nq | q_x | q_y | q_z Notes ### INTRODUCTION
> >     Purpose of matdyn.x:

> >     This program calculates the phonon frequencies for a list of generic
> >     q vectors starting from the interatomic force constants generated
> >     from the dynamical matrices as written by DFPT phonon code through
> >     the companion program q2r.x

> >     matdyn.x can generate a supercell of the original cell for mass
> >     approximation calculation. If supercell data are not specified
> >     in input, the unit cell, lattice vectors, atom types and positions
> >     are read from the force constant file.

> >     Input data format: [ ] = it depends

> >     Structure of the input data:
> >     ========================================================================

> >     &INPUT
> >        ...specs of the namelist variables...
> >     /

> >     [ X(1)   Y(1)   Z(1)    ityp(1)
> >       ...
> >       X(nat) Y(nat) Z(nat)  ityp(nat) ]

> >     [ nq
> >       q_x(1)  q_y(1)  q_x(1)   [ nptq(1) ]
> >       ...
> >       q_x(nq) q_y(nq) q_x(nq)  [ nptq(1) ] ]
## Namelist: &INPUT
flfrc | CHARACTER
>     File produced by q2r containing force constants (needed)
>     It is the same as in the input of q2r.x (+ the .xml extension
>     if the dynamical matrices produced by ph.x were in xml
>     format). No default value: must be specified.
[Back to Top]
asr | CHARACTER
Default: | 'no'
>     Indicates the type of Acoustic Sum Rule imposed.

>     Allowed values:
>   `'no' :`
>       no Acoustic Sum Rules imposed (default)
>   `'simple' :`
>       previous implementation of the asr used
>       (3 translational asr imposed by correction of
>        the diagonal elements of the force constants matrix)
>   `'crystal' :`
>       3 translational asr imposed by optimized
>       correction of the force constants (projection)
>   `'one-dim' :`
>       3 translational asr + 1 rotational asr imposed
>       by optimized correction of the dyn. mat. (the
>       rotation axis is the direction of periodicity; it
>       will work only if this axis considered is one of
>       the Cartesian axis).
>   `'zero-dim' :`
>       3 translational asr + 3 rotational asr imposed
>       by optimized correction of the dyn. mat.
>     Note that in certain cases, not all the rotational asr
>     can be applied (e.g. if there are only 2 atoms in a
>     molecule or if all the atoms are aligned, etc.).
>     In these cases the supplementary asr are cancelled
>     during the orthonormalization procedure (see below).
[Back to Top]
dos | LOGICAL
>     if .true. calculate phonon Density of States (DOS)
>     using tetrahedra and a uniform q-point grid (see below)
>     NB: may not work properly in noncubic materials

>     if .false. calculate phonon bands from the list of q-points
>     supplied in input (default)
[Back to Top]
nk1, nk2, nk3 | INTEGER
>     uniform q-point grid for DOS calculation (includes q=0)
>     (must be specified if dos = .true., ignored otherwise)
[Back to Top]
deltaE | REAL
>     energy step, in cm-1, for DOS calculation: from min
>     to max phonon energy (default: 1 cm-1 if ndos, see
>     below, is not specified)
[Back to Top]
ndos | INTEGER
>     number of energy steps for DOS calculations
>     (default: calculated from deltaE if not specified)
[Back to Top]
degauss | REAL
>     DOS broadening in cm-1

>     Default: 0 - meaning use tetrahedra
[Back to Top]
fldos | CHARACTER
>     output file for dos (default: 'matdyn.dos')
>     the dos is in states/cm-1 plotted vs omega in cm(-1)
>     and is normalised to 3*nat, i.e. the number of phonons
[Back to Top]
flfrq | CHARACTER
>     output file for frequencies (default: 'matdyn.freq')
[Back to Top]
flvec | CHARACTER
>     output file for normalized phonon displacements
>     (default: 'matdyn.modes'). The normalized phonon displacements
>     are the eigenvectors divided by the square root of the mass,
>     then normalized. As such they are not orthogonal.
[Back to Top]
fleig | CHARACTER
>     output file for phonon eigenvectors (default: 'matdyn.eig')
>     The phonon eigenvectors are the eigenvectors of the dynamical
>     matrix. They are orthogonal.
[Back to Top]
fldyn | CHARACTER
>     output file for dynamical matrix (default: ' ' i.e. not written)
[Back to Top]
at(i,j), (i,j) = (1,1) ... (3,3) | REAL
>     supercell lattice vectors - must form a superlattice of the
>     original lattice (default: use original cell)
[Back to Top]
l1, l2, l3 | INTEGER
>     supercell lattice vectors are original cell vectors times
>     l1, l2, l3 respectively (default: 1, ignored if at specified)
[Back to Top]
ntyp | INTEGER
>     number of atom types in the supercell
>     (default: ntyp of the original cell)
[Back to Top]
amass(i), i=1,ntyp | REAL
>     masses of atoms in the supercell (a.m.u.), one per atom type
>     (default: use masses read from file flfrc)
[Back to Top]
readtau | LOGICAL
>     read  atomic positions of the supercell from input
>     (used to specify different masses) (default: .false.)
[Back to Top]
fltau | CHARACTER
>     write atomic positions of the supercell to file fltau
>     (default: fltau = ' ', do not write)
[Back to Top]
la2F | LOGICAL
>     if .true. interpolates also the el-ph coefficients
[Back to Top]
q_in_band_form | LOGICAL
>     if .true. the q points are given in band form:
>     only the first and last point of one or more lines
>     are given. See below. (default: .false.).
[Back to Top]
q_in_cryst_coord | LOGICAL
>     if .true. input q points are in crystalline
>     coordinates (default: .false.)
[Back to Top]
eigen_similarity | LOGICAL
>     use similarity of the displacements to order
>     frequencies  (default: .false.)

>     NB: You cannot use this option with the symmetry
>     analysis of the modes.
[Back to Top]
fd | LOGICAL
>     if .true. the ifc come from the finite displacement calculation
[Back to Top]
na_ifc | LOGICAL
>     add non analitic contributions to the interatomic force
>     constants if finite displacement method is used (as in Wang et al.
>     PRB 85, 224303 (2012)) [to be used in conjunction with fd.x]
[Back to Top]
nosym | LOGICAL
>     if .true., no symmetry and no time reversal are imposed
[Back to Top]
loto_2d | LOGICAL
>     set to .true. to activate two-dimensional treatment of LO-TO splitting
[Back to Top]
loto_disable | LOGICAL
>     if .true. do not apply LO-TO splitting for q=0
>     (default: .false.)
[Back to Top]
> IF `readtau == .true. :`
> ## Card: AtomicPositionSpecs
> > if (readtau) atomic positions must be specified as follows: ### Syntax:
> > X(1) | Y(1) | Z(1) | ityp(1)
> > X(2) | Y(2) | Z(2) | ityp(2)
> > . . .
> > X(nat) | Y(nat) | Z(nat) | ityp(nat)
> > ### Description of items:
> > X, Y, Z | REAL
> > >     X, Y, Z atomic positions
> > [Back to Top]
> > ityp | INTEGER
> > >     index of the atomic type
> [Back to Top]
> IF `q_in_band_form == .true .and. dos == .false. :`
> ## Card: qPointsSpecs
> > if (q_in_band_form .and. .not.dos) q-points must be specified as follows: ### Syntax: nq
> > q_x(1) | q_y(1) | q_z(1) | nptq(1)
> > q_x(2) | q_y(2) | q_z(2) | nptq(2)
> > . . .
> > q_x(nq) | q_y(nq) | q_z(nq) | nptq(nq)
> > ### Description of items:
> > nq | INTEGER
> > >     number of q points
> > [Back to Top]
> > q_x, q_y, q_z | REAL
> > >     coordinates of the Q point
> > [Back to Top]
> > nptq | INTEGER
> > >     The number of points between this point and the next.

> > >     nptq is the number of points between this point
> > >     and the next. These points are automatically
> > >     generated. the q points are given in Cartesian
> > >     coordinates, 2pi/a units (a = lattice parameters)
> [Back to Top]
> ELSEIF `dos == .false. :`
> if (.not. dos) q-points must be specified as follows:
> ## Card: qPointsSpecs
> > ### Syntax: nq
> > q_x(1) | q_y(1) | q_z(1)
> > q_x(2) | q_y(2) | q_z(2)
> > . . .
> > q_x(nq) | q_y(nq) | q_z(nq)
> > ### Description of items:
> > nq | INTEGER
> > >     number of q points
> > [Back to Top]
> > q_x, q_y, q_z | REAL
> > >     q-points in cartesian coordinates, 2pi/a units (a = lattice parameters)
> [Back to Top]
> > ### Notes
> >     If q = 0, the direction qhat (q=>0) for the non-analytic part
> >     is extracted from the sequence of q-points as follows:

> >     qhat = q(n) - q(n-1)   or   qhat = q(n) - q(n+1)

> >     depending on which one is available and nonzero.

> >     For low-symmetry crystals, specify twice q = 0 in the list
> >     if you want to have q = 0 results for two different directions

This file has been created by helpdoc utility on Thu Apr 22 16:16:32 CEST 2021.