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<input_description distribution="Quantum Espresso" package="turboEELS" program="turbo_eels.x" >
   <toc>
   </toc>
   <intro>
    Input data format: { } = optional, [ ] = it depends.

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

BEWARE: TABS, DOS &lt;CR&gt;&lt;LF&gt; CHARACTERS ARE POTENTIAL SOURCES OF TROUBLE

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

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

&amp;lr_input
  ...
/

&amp;lr_control
  ...
/
   </intro>
   <namelist name="lr_input" >
      <label> This namelist is always needed !
      </label>
      <var name="prefix" type="CHARACTER" >
         <default> &apos;pwscf&apos;
         </default>
         <info>
Sets the prefix for generated and read files. The files
generated by the ground state pw.x run must have this
same prefix.
         </info>
      </var>
      <var name="outdir" type="CHARACTER" >
         <default> &apos;./&apos;
         </default>
         <info>
The directory that contains the run critical files, which
include the files generated by ground state pw.x run.
         </info>
      </var>
      <var name="restart" type="LOGICAL" >
         <default> .false.
         </default>
         <info>
When set to .true., turbo_eels.x will attempt to restart
from a previous interrupted calculation. (see <ref>restart_step</ref>
variable).
Beware, if set to .false. turbo_eels.x will OVERWRITE any
previous runs.
         </info>
      </var>
      <var name="restart_step" type="INTEGER" >
         <default> itermax
         </default>
         <info>
The code writes restart files every restart_step iterations.
Restart files are automatically written at the end of
itermax Lanczos steps.
         </info>
      </var>
      <var name="lr_verbosity" type="INTEGER" >
         <default> 1
         </default>
         <info>
This integer variable controls the amount of information
written to standard output.
         </info>
      </var>
      <var name="disk_io" type="CHARACTER" >
         <default> &apos;default&apos;
         </default>
         <info>
    Fine control of disk usage. Currently only &apos;reduced&apos; is
supported where no restart files are written, apart from
the &apos;default&apos; mode.
         </info>
      </var>
   </namelist>
   <namelist name="lr_control" >
      <var name="approximation" type="CHARACTER" >
         <default> &apos;TDDFT&apos;
         </default>
         <options>
            <info> A string describing a level of theory:
            </info>
            <opt val="'TDDFT'" >
Time-Dependent Local Density Approximation or
Time-Dependent Generalized Gradient Approximation
(depending on the XC functional)
            </opt>
            <opt val="'IPA'" >
Independent Particle Approximation (IPA)
            </opt>
            <opt val="'RPA_with_CLFE'" >
Random Phase Approximation (RPA) with
Crystal Local Field Effects (CLFE)
            </opt>
         </options>
      </var>
      <vargroup type="REAL" >
         <var name="q1" >
         </var>
         <var name="q2" >
         </var>
         <var name="q3" >
         </var>
         <default> 1.0, 1.0, 1.0
         </default>
         <info>
The values of the transferred momentum q = (q1, q2, q3)
in Cartesian coordinates in units of 2pi/a, where
&quot;a&quot; is the lattice parameter.
         </info>
      </vargroup>
      <var name="calculator" type="CHARACTER" >
         <default> &apos;lanczos&apos;
         </default>
         <options>
            <info>
Variable that controls which algorithm is used to compute EELS spectra.
            </info>
            <opt val="'lanczos'" >
corresponds to the Lanczos recursive algorithm
            </opt>
            <opt val="'sternheimer'" >
corresponds to the Sternheimer algorithm
            </opt>
         </options>
      </var>
      <var name="itermax" type="INTEGER" >
         <default> 500
         </default>
         <info>
When <ref>calculator</ref> = &apos;lanczos&apos;, <ref>itermax</ref> is the
maximum number of Lanczos iterations that will be performed.
When <ref>calculator</ref> = &apos;sternheimer&apos;, <ref>itermax</ref> is the
maximum number of iterations in a SCF step for each frequency.
         </info>
      </var>
      <var name="pseudo_hermitian" type="LOGICAL" >
         <default> .true.
         </default>
         <info>
This variable is used only when <ref>calculator</ref> = &apos;lanczos&apos;.
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).
         </info>
      </var>
      <var name="alpha_mix(i)" type="REAL" >
         <default> alpha_mix(1)=0.7
         </default>
         <info>
This variable is used only when <ref>calculator</ref> = &apos;sternheimer&apos;.
Mixing parameter (for the i-th iteration) for updating
the response SCF potential using the modified Broyden
method: D.D. Johnson, <a href="https://journals.aps.org/prb/abstract/10.1103/PhysRevB.38.12807">PRB 38, 12807 (1988)</a>.
         </info>
      </var>
      <var name="epsil" type="REAL" >
         <default> 0.02
         </default>
         <info>
This variable is used only when <ref>calculator</ref> = &apos;sternheimer&apos;.
The broadening/damping term (in Rydberg units).
         </info>
      </var>
      <var name="units" type="INTEGER" >
         <default> 0
         </default>
         <info>
This variable is used only when <ref>calculator</ref> = &apos;sternheimer&apos;.
The unit system used for the output, for <ref>start</ref>, <ref>end</ref>,
and <ref>increment</ref> input parameters.
0 = Rydbergs, 1 = Electron volts.
         </info>
      </var>
      <var name="start" type="REAL" >
         <default> 0.0
         </default>
         <see> end, increment
         </see>
         <info>
This variable is used only when <ref>calculator</ref> = &apos;sternheimer&apos;.
<ref>start</ref> is the value of frequency starting from which the
susceptibility and the loss function (-Im(1/eps)) will be computed.
<ref>start</ref> is specified in units controlled by <ref>units</ref>.
         </info>
      </var>
      <var name="end" type="REAL" >
         <default> 2.5
         </default>
         <see> start, increment
         </see>
         <info>
This variable is used only when <ref>calculator</ref> = &apos;sternheimer&apos;.
<ref>end</ref> is the value of frequency up to which the
susceptibility and the loss function (-Im(1/eps)) will be computed.
<ref>end</ref> is specified in units controlled by <ref>units</ref>.
         </info>
      </var>
      <var name="increment" type="REAL" >
         <default> 0.001
         </default>
         <see> start, end
         </see>
         <info>
This variable is used only when <ref>calculator</ref> = &apos;sternheimer&apos;.
<ref>increment</ref> is an incremental step used to define the mesh
of frequencies between <ref>start</ref> and <ref>end</ref>.
<ref>increment</ref> is specified in units controlled by <ref>units</ref>.
         </info>
      </var>
   </namelist>
</input_description>