Input File Description

Program: turbo_eels.x / turboEELS / Quantum Espresso

TABLE OF CONTENTS

INTRODUCTION

&lr_input

prefix | outdir | restart | restart_step | lr_verbosity | disk_io

&lr_control

approximation | q1 | q2 | q3 | calculator | itermax | pseudo_hermitian | alpha_mix(i) | epsil | units | start | end | increment

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
  ...
/
   

Namelist: &lr_input

This namelist is always needed !

prefix CHARACTER
Default: 'pwscf'
Sets the prefix for generated and read files. The files
generated by the ground state pw.x run must 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.
         
restart LOGICAL
Default: .false.
When set to .true., turbo_eels.x will attempt to restart
from a previous interrupted calculation. (see restart_step
variable).
Beware, if set to .false. turbo_eels.x will OVERWRITE any
previous runs.
         
restart_step 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

approximation CHARACTER
Default: 'TDDFT'
 A string describing a level of theory:
            
'TDDFT' :
Time-Dependent Local Density Approximation or
Time-Dependent Generalized Gradient Approximation
(depending on the XC functional)
            
'IPA' :
Independent Particle Approximation (IPA)
            
'RPA_with_CLFE' :
Random Phase Approximation (RPA) with
Crystal Local Field Effects (CLFE)
            
q1, q2, q3 REAL
Default: 1.0, 1.0, 1.0
The values of the transferred momentum q = (q1, q2, q3)
in Cartesian coordinates in units of 2pi/a, where
"a" is the lattice parameter.
         
calculator CHARACTER
Default: 'lanczos'
Variable that controls which algorithm is used to compute EELS spectra.
            
'lanczos' :
corresponds to the Lanczos recursive algorithm
            
'sternheimer' :
corresponds to the Sternheimer algorithm
            
itermax INTEGER
Default: 500
When calculator = 'lanczos', itermax is the
maximum number of Lanczos iterations that will be performed.
When calculator = 'sternheimer', itermax is the
maximum number of iterations in a SCF step for each frequency.
         
pseudo_hermitian LOGICAL
Default: .true.
This variable is used only when calculator = 'lanczos'.
When set to .true. the pseudo-Hermitian Lanczos algorithm is
used. When set to .false. the non-Hermitian Lanczos
biorthogonalization algorithm is used (which is two times slower).
         
alpha_mix(i) REAL
Default: alpha_mix(1)=0.7
This variable is used only when calculator = 'sternheimer'.
Mixing parameter (for the i-th iteration) for updating
the response SCF potential using the modified Broyden
method: D.D. Johnson, PRB 38, 12807 (1988).
         
epsil REAL
Default: 0.02
This variable is used only when calculator = 'sternheimer'.
The broadening/damping term (in Rydberg units).
         
units INTEGER
Default: 0
This variable is used only when calculator = 'sternheimer'.
The unit system used for the output, for start, end,
and increment input parameters.
0 = Rydbergs, 1 = Electron volts.
         
start REAL
Default: 0.0
See: end, increment
This variable is used only when calculator = 'sternheimer'.
start is the value of frequency starting from which the
susceptibility and the loss function (-Im(1/eps)) will be computed.
start is specified in units controlled by units.
         
end REAL
Default: 2.5
See: start, increment
This variable is used only when calculator = 'sternheimer'.
end is the value of frequency up to which the
susceptibility and the loss function (-Im(1/eps)) will be computed.
end is specified in units controlled by units.
         
increment REAL
Default: 0.001
See: start, end
This variable is used only when calculator = 'sternheimer'.
increment is an incremental step used to define the mesh
of frequencies between start and end.
increment is specified in units controlled by units.
         
This file has been created by helpdoc utility.