    ------------------------------------------------------------------------
    INPUT FILE DESCRIPTION

    Program: bands.x / PWscf / Quantum Espresso (version: 6.6)
    ------------------------------------------------------------------------

    Purpose of bands.x:
       Re-order bands, computes band-related properties. Currently,
       re-ordering can be done with two different algorithms:
       (a) by maximising the overlap with bands at previous k-point
       (b) by computing symmetry properties of each wavefunction
       Bands-related properties that can be computed are currently
       (a) The expectation value of the spin operator on each spinor
           wave-function (noncolinear case only)
       (b) The expectation value of p

    The input data can be read from standard input or from file using
    command-line options "bands.x -i file-name" (same syntax as for pw.x)

    Output files:
    - file "filband" containing the band structure, in a format
      suitable for plotting code "plotband.x"
    - file "filband".rap (if "lsym" is .t.)  with symmetry information,
      to be read by plotting code "plotband.x"
    - if ("lsigma"(i)): file "filband".i, i=1,2,3, with expectation values
      of the spin operator in the noncolinear case
    - file "filband".gnu with bands in eV, directly plottable using gnuplot
    - file "filp" with matrix elements of p

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

       &BANDS
         ...
       /

    ========================================================================
    NAMELIST: &BANDS

       +--------------------------------------------------------------------
       Variable:       prefix

       Type:           CHARACTER
       Default:        'pwscf'
       Description:    prefix of files saved by program pw.x
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       outdir

       Type:           CHARACTER
       Description:    directory containing the input data, i.e. the same as in pw.x
       Default:        value of the ESPRESSO_TMPDIR environment variable if set;
                       current directory ('./') otherwise
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       filband

       Type:           CHARACTER
       Default:        'bands.out'
       Description:    file name for band output (to be read by "plotband.x")
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       spin_component

       Type:           INTEGER
       Description:    In the lsda case select:

                          1 = spin-up
                          2 = spin-down
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       lsigma(i), i=1,3

       Type:           LOGICAL
       Description:    If true computes expectation values of the spin operator
                       on the spinor wave-functions (only in the noncollinear case),
                       writes them to a file "filband".i, i=1,2,3
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       lp

       Type:           LOGICAL
       Default:        .false.
       Description:    If .true. matrix elements of the momentum operator p between
                       conduction and valence bands are computed and written to file
                       specified in "filp"
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       filp

       Type:           CHARACTER
       Default:        'p_avg.dat'
       Description:    If "lp" is set to .true., file name for matrix elements of p
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       lsym

       Type:           LOGICAL
       Default:        .true.
       Description:    If .true. the bands are classified according to the
                       irreducible representations of the small group of k.
                       A file "filband".rap with the same format of "filband"
                       is written, for usage by "plotband.x"
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       no_overlap

       Type:           LOGICAL
       Default:        .true.
       Description:    If .false., and if "lsym" is .false., writes the eigenvalues
                       in the order that maximises overlap with the neighbor k-points
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variable:       plot_2d

       Type:           LOGICAL
       Default:        .false.
       Description:    If .true. writes the eigenvalues in the output file
                       in a 2D format readable by gnuplot. Band ordering is not
                       changed. Each band is written in a different file called
                       filband.# with the format:

                          xk, yk, energy
                          xk, yk, energy
                          ..  ..  ..

                       energies are written in eV and xk in units 2\pi/a.
       +--------------------------------------------------------------------

       +--------------------------------------------------------------------
       Variables:      firstk, lastk

       Type:           INTEGER
       Description:    if @ref lsym=.true. makes the symmetry analysis only for k
                       points between firstk to lastk
       +--------------------------------------------------------------------

    ===END OF NAMELIST======================================================

    This file has been created by helpdoc utility on Wed Dec 02 08:04:46 CET 2020