# Input File Description

## Program: turbo_eels.x / turboEELS / Quantum ESPRESSO (version: 7.2)

> ### 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 | ethr_nscf

> ### 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.

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outdir | CHARACTER
Default: | './'

>     The directory that contains the run critical files, which
>     include the files generated by ground state pw.x run.

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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.

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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.

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lr_verbosity | INTEGER
Default: | 1

>     This integer variable controls the amount of information
>     written to standard output.

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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.

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## 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)

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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.

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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

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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.

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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).

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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).

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epsil | REAL
Default: | 0.02

>     This variable is used only when calculator = 'sternheimer'.
>     The broadening/damping term (in Rydberg units).

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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.

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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.

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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.

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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.

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ethr_nscf | REAL
Default: | 1.D-11

>     Threshold for the convergence of eigenvalues during
>     the iterative diagonalization of the Hamiltonian in
>     the non-self-consistent-field (NSCF) calculation at
>     k and k+q points. Note, this quantity is NOT extensive.

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This file has been created by helpdoc utility on Sat Mar 18 15:45:37 CET 2023.