Input File Description

Program: turbo_lanczos.x / turboTDDFPT / Quantum Espresso

TABLE OF CONTENTS

INTRODUCTION

&lr_input

title | prefix | outdir | wfcdir | restart | restart | lr_verbosity | disk_io

&lr_control

itermax | ipol | nipol | ltammd | no_hxc | ecutfock | charge_response

&lr_post

omeg | epsil | beta_gamma_z_prefix | w_T_npol | plot_type

INTRODUCTION

    Input data format: { } = optional, [ ] = it depends.

All quantities whose dimensions are not explicitly specified are in
RYDBERG ATOMIC UNITS

BEWARE: TABS, DOS <CR><LF> CHARACTERS ARE POTENTIAL SOURCES OF TROUBLE

Comment lines in namelists can be introduced by a "!", exactly as in
fortran code. Comments lines in ``cards'' can be introduced by
either a "!" or a "#" character in the first position of a line.

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

&lr_input
  ...
/

&lr_control
  ...
/

[ &lr_post
  ...
 / ]
   

Namelist: lr_input

This namelist is always needed !

title CHARACTER
Status: OPTIONAL
 A string describing the job.
         
prefix CHARACTER
Default: 'pwscf'
Sets the prefix for generated and read files. The files
generated by the ground state pw.x run should have this
same prefix.
         
outdir CHARACTER
Default: './'
The directory that contains the run critical files, which
include the files generated by ground state pw.x run.
         
wfcdir CHARACTER
Default: './'
The directory that contains the run critical files, which
include the files generated by ground state pw.x run.
         
restart LOGICAL
Default: .false.
When set to .true., turbo_lanczos.x will attempt to restart
from a previous interrupted calculation. (see restart_step
variable).

Beware, if set to .false. turbo_lanczos.x will OVERWRITE any
previous runs.
         
restart INTEGER
Default: itermax
The code writes restart files every restart step iterations.
Restart files are automatically written at the end of
itermax Lanczos steps.
         
lr_verbosity INTEGER
Default: 1
This integer variable controls the amount of information
written to standard output.
         
disk_io CHARACTER
Default: 'default'
    Fine control of disk usage. Currently only 'reduced' is
supported where no restart files are written, apart from
the 'default' mode.
         

Namelist: lr_control

itermax INTEGER
Default: 500
Number of iterations to be performed.
         
ipol INTEGER
Default: 1
An integer variable that determines which element of the
dynamical polarizability will be computed:
1 -> alpha_xx(omega), 2 -> alpha_yy(omega), and
3 -> alpha_zz(omega). When set to 4, three Lanczos chains
are sequentially performed and the full polarizability
tensor and the absorption coefficient are computed.
         
nipol INTEGER
Default: 1 if ipol < 4; 3 if ipol=4
    Determines the number of zeta coefficients to be calculated
for a given polarization direction.
         
ltammd LOGICAL
Default: .false.
When set to .true. the Tamm-Dancoff approximation is used
in constructing the Liouvillian.
         
no_hxc LOGICAL
Default: .false.
When set to .true. the change in the internal field
(Hartree and exchange-correlation) is ignored in the
calculation, resulting in the independent electron
approximation.
         
ecutfock REAL
Default: ecutrho
kinetic energy cutoff (Ry) for the exact exchange operator in
EXX type calculations. By default this is the same as ecutrho
but in some EXX calculations significant speed-up can be found
by reducing ecutfock, at the expense of some loss in accuracy.
Currently only implemented for the optimized gamma point only
calculations.
         
charge_response INTEGER
Default: 0
When set to 1, the code computes the response of the charge
density and writes it into a file format determined by the
variable plot type. Setting charge response to 1 makes the
presence of the card lr post mandatory.
         

Namelist: lr_post

omeg REAL
Default: 0.0
    The response of the charge density is calculated for this
transition energy (in Rydberg units)
         
epsil REAL
Default: 0.0
The broadening/damping term (in Rydberg units).
         
beta_gamma_z_prefix CHARACTER
Default: 'pwscf'
The prefix of the file where the beta gamma zeta coefficients
from the first calculation can be set manually using this
parameter. The file outdir/beta gamma z prefix.beta gamma z.x
(where x=1-3) must exist.
         
w_T_npol INTEGER
Default: 1
Number of polarization directions considered in the previous
calculation. It must be set to 3 if in the previous calculation
 ipol=4, it must be set to 1 otherwise.
         
plot_type INTEGER
Default: 1
    An integer variable that determines the format of the file
containing the charge density response. 1: A file containing
the x y z grid coordinates and the corre- sponding value of
the density is produced 2: The density response is written
in Xcrysden format 3: The density response is written in
the gaussian cube format.
         
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