mirror of https://gitlab.com/QEF/q-e.git
474 lines
19 KiB
Plaintext
474 lines
19 KiB
Plaintext
*** FILE AUTOMATICALLY CREATED: DO NOT EDIT, CHANGES WILL BE LOST ***
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------------------------------------------------------------------------
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INPUT FILE DESCRIPTION
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Program: neb.x / NEB / Quantum Espresso (version: 6.4)
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------------------------------------------------------------------------
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Input data format: { } = optional, [ ] = it depends, | = or
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All quantities whose dimensions are not explicitly specified are in
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RYDBERG ATOMIC UNITS
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BEWARE: TABS, DOS <CR><LF> CHARACTERS ARE POTENTIAL SOURCES OF TROUBLE
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neb.x DOES NOT READ FROM STANDARD INPUT !
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There are two ways for running a calculation with neb.x:
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(1) specifying a file to parse with the ./neb.x -inp or ./neb.x -input
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command line option.
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(2) or specifying the number of copies of PWscf inputs with the ./neb.x -input_images
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For case (1) a file containing special KEYWORDS (aka SUPERCARDS) has to be
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written (see below). These KEYWORDS tell the parser which part of the file
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contains the neb specifics and which part contains the energy/force engine
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input (at the moment only PW). After the parsing, different files are
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generated: neb.dat, with the neb specific variables, and a set of pw_*.in
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PWscf input files, i.e., one for each input position. All options for a
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single SCF calculation apply.
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The general structure of the file to be parsed is:
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==================================================
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BEGIN
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BEGIN_PATH_INPUT
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... neb specific namelists and cards
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END_PATH_INPUT
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BEGIN_ENGINE_INPUT
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...pw specific namelists and cards
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BEGIN_POSITIONS
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FIRST_IMAGE
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...pw ATOMIC_POSITIONS card
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INTERMEDIATE_IMAGE
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...pw ATOMIC_POSITIONS card
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LAST_IMAGE
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...pw ATOMIC_POSITIONS card
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END_POSITIONS
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... other pw specific cards
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END_ENGINE_INPUT
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END
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For case (2) neb.dat and all pw_1.in, pw_2.in ... should be already present.
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Structure of the NEB-only input data (file neb.dat):
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====================================================
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&PATH
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...
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/
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[ CLIMBING_IMAGES
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list of images, separated by a comma ]
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########################################################################
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| SUPERCARD: BEGIN/END
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| this supercard is enclosed within the keywords:
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| BEGIN
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| ... content of the supercard here ...
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| END
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| The syntax of supercard's content follows below:
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########################################################################
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| SUPERCARD: BEGIN_PATH_INPUT/END_PATH_INPUT
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| this supercard is enclosed within the keywords:
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| BEGIN_PATH_INPUT
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| ... content of the supercard here ...
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| END_PATH_INPUT
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| The syntax of supercard's content follows below:
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========================================================================
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NAMELIST: &PATH
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+--------------------------------------------------------------------
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Variable: string_method
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Type: CHARACTER
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Default: 'neb'
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Description:
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A string describing the task to be performed. Options are:
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'neb' :
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nudget-elastic-band
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'smd' :
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string-method-dynamics
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: restart_mode
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Type: CHARACTER
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Default: 'from_scratch'
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Description:
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Options are:
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'from_scratch' :
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from scratch
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'restart' :
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from previous interrupted run
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: nstep_path
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Type: INTEGER
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Description: number of ionic + electronic steps
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Default: 1
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: num_of_images
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Type: INTEGER
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Default: 0
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Description: Number of points used to discretize the path
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(it must be larger than 3).
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: opt_scheme
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Type: CHARACTER
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Default: 'quick-min'
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Description:
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Specify the type of optimization scheme:
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'sd' :
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steepest descent
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'broyden' :
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quasi-Newton Broyden's second method (suggested)
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'broyden2' :
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another variant of the quasi-Newton Broyden's
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second method to be tested and compared with the
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previous one.
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'quick-min' :
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an optimisation algorithm based on the
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projected velocity Verlet scheme
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'langevin' :
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finite temperature langevin dynamics of the
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string (smd only). It is used to compute the
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average path and the free-energy profile.
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: CI_scheme
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Type: CHARACTER
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Default: 'no-CI'
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Description:
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Specify the type of Climbing Image scheme:
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'no-CI' :
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climbing image is not used
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'auto' :
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original CI scheme. The image highest in energy
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does not feel the effect of springs and is
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allowed to climb along the path
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'manual' :
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images that have to climb are manually selected.
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See also "CLIMBING_IMAGES" card
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: first_last_opt
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Type: LOGICAL
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Default: .FALSE.
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Description: Also the first and the last configurations are optimized
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"on the fly" (these images do not feel the effect of the springs).
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: minimum_image
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Type: LOGICAL
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Default: .FALSE.
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Description: Assume a "minimum image criterion" to build the path. If an atom
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moves by more than half the length of a crystal axis between one
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image and the next in the input (before interpolation),
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an appropriate periodic replica of that atom is chosen.
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Useful to avoid jumps in the initial reaction path.
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: temp_req
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Type: REAL
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Default: 0.D0 Kelvin
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Description: Temperature used for the langevin dynamics of the string.
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: ds
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Type: REAL
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Default: 1.D0
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Description: Optimisation step length ( Hartree atomic units ).
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If "opt_scheme"=="broyden", ds is used as a guess for the
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diagonal part of the Jacobian matrix.
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variables: k_max, k_min
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Type: REAL
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Default: 0.1D0 Hartree atomic units
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Description: Set them to use a Variable Elastic Constants scheme
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elastic constants are in the range [ k_min, k_max ]
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this is useful to rise the resolution around the saddle point.
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: path_thr
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Type: REAL
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Default: 0.05D0 eV / Angstrom
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Description: The simulation stops when the error ( the norm of the force
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orthogonal to the path in eV/A ) is less than path_thr.
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: use_masses
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Type: LOGICAL
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Default: .FALSE.
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Description: If. TRUE. the optimisation of the path is performed using
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mass-weighted coordinates. Useful together with quick-min
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optimization scheme, if some bonds are much stiffer than
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others. By assigning a larger (fictitious) mass to atoms
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with stiff bonds, one may use a longer time step "ds"
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: use_freezing
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Type: LOGICAL
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Default: .FALSE.
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Description: If. TRUE. the images are optimised according to their error:
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only those images with an error larger than half of the largest
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are optimised. The other images are kept frozen.
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: lfcpopt
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Type: LOGICAL
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See: fcp_mu
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Default: .FALSE.
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Description: If .TRUE. perform a constant bias potential (constant-mu)
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calculation with ESM method (assume_isolated = 'esm' and
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esm_bc = 'bc2' or 'bc3' must be set in SYSTEM namelist).
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"fcp_mu" gives the target Fermi energy.
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See the header of PW/src/fcp.f90 for documentation
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: fcp_mu
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Type: REAL
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See: lfcpopt
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Default: 0.d0
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Description: If "lfcpopt" == .TRUE., gives the target Fermi energy [Ry].
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One can specify the total charge of the system for the first
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and last image by giving "fcp_tot_charge_first" and "fcp_tot_charge_last"
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so that the Fermi energy of these systems will be the target value,
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otherwise "first_last_opt" should be .TRUE.
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: fcp_tot_charge_first
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Type: REAL
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See: lfcpopt
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Default: 0.d0
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Description: Total charge of the system ('tot_charge') for the first image.
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Initial 'tot_charge' for intermediate images will be given by
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linear interpolation of "fcp_tot_charge_first" and "fcp_tot_charge_last"
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+--------------------------------------------------------------------
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+--------------------------------------------------------------------
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Variable: fcp_tot_charge_last
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Type: REAL
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See: lfcpopt
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Default: 0.d0
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Description: Total charge of the system ('tot_charge') for the last image.
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Initial 'tot_charge' for intermediate images will be given by
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linear interpolation of "fcp_tot_charge_first" and "fcp_tot_charge_last"
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+--------------------------------------------------------------------
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===END OF NAMELIST======================================================
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========================================================================
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CARD: CLIMBING_IMAGES
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OPTIONAL CARD, NEEDED ONLY IF "CI_SCHEME" == 'MANUAL', IGNORED OTHERWISE !
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/////////////////////////////////////////
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// Syntax: //
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/////////////////////////////////////////
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CLIMBING_IMAGES
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index1, index2, ... indexN
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/////////////////////////////////////////
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DESCRIPTION OF ITEMS:
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+--------------------------------------------------------------------
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Variables: index1, index2, ... indexN
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Type: INTEGER
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Description: index1, index2, ..., indexN are indices of the images to which the
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Climbing-Image procedure apply. If more than one image is specified
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they must be separated by a comma.
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+--------------------------------------------------------------------
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===END OF CARD==========================================================
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### END OF SUPERCARD : BEGIN_PATH_INPUT/END_PATH_INPUT ################
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########################################################################
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| SUPERCARD: BEGIN_ENGINE_INPUT/END_ENGINE_INPUT
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| this supercard is enclosed within the keywords:
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| BEGIN_ENGINE_INPUT
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| ... content of the supercard here ...
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| END_ENGINE_INPUT
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| The syntax of supercard's content follows below:
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Here comes the pw.x specific namelists and cards (see file: "" or INPUT_PW.txt)
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with the exception of "ATOMIC_POSITIONS" cards, which are specified separately within the
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"BEGIN_POSITIONS"/END_POSITIONS supercard as described below.
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So the input that follows here is of the following structure:
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&CONTROL
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...
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/
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&SYSTEM
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...
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/
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&ELECTRONS
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...
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/
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...
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########################################################################
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| SUPERCARD: BEGIN_POSITIONS/END_POSITIONS
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| this supercard is enclosed within the keywords:
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| BEGIN_POSITIONS
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| ... content of the supercard here ...
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| END_POSITIONS
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| The syntax of supercard's content follows below:
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NB:
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Atomic positions for all the images are specified within the "BEGIN_POSITIONS" / END_POSITIONS
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supercard, where each instance of "ATOMIC_POSITIONS" card is prefixed either by "FIRST_IMAGE",
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"INTERMEDIATE_IMAGE", or "LAST_IMAGE" keywords.
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Note that intermediate images are optional, i.e., there can be none or any number of
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"INTERMEDIATE_IMAGE" images.
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########################################################################
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| SUPERCARD: FIRST_IMAGE
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| this supercard starts with the keyword:
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| FIRST_IMAGE
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| ... content of the supercard here ...
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| The syntax of supercard's content follows below:
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========================================================================
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CARD: ATOMIC_POSITIONS { alat | bohr | angstrom | crystal | crystal_sg }
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For the description of ATOMIC_POSITIONS card see file: "" or INPUT_PW.txt
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===END OF CARD==========================================================
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### END OF SUPERCARD : FIRST_IMAGE ####################################
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########################################################################
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| SUPERCARD: INTERMEDIATE_IMAGE
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| this supercard starts with the keyword:
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| INTERMEDIATE_IMAGE
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| ... content of the supercard here ...
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| REMARK:
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| There can be any number (including zero) of INTERMEDIATE_IMAGE supercards.
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| The syntax of supercard's content follows below:
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========================================================================
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CARD: ATOMIC_POSITIONS { alat | bohr | angstrom | crystal | crystal_sg }
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For the description of ATOMIC_POSITIONS card see file: "" or INPUT_PW.txt
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===END OF CARD==========================================================
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### END OF SUPERCARD : INTERMEDIATE_IMAGE #############################
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########################################################################
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| SUPERCARD: LAST_IMAGE
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| this supercard starts with the keyword:
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| LAST_IMAGE
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| ... content of the supercard here ...
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| The syntax of supercard's content follows below:
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========================================================================
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CARD: ATOMIC_POSITIONS { alat | bohr | angstrom | crystal | crystal_sg }
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For the description of ATOMIC_POSITIONS card see file: "" or INPUT_PW.txt
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===END OF CARD==========================================================
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### END OF SUPERCARD : LAST_IMAGE #####################################
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### END OF SUPERCARD : BEGIN_POSITIONS/END_POSITIONS ##################
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Here can follow other pw specific cards ...
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### END OF SUPERCARD : BEGIN_ENGINE_INPUT/END_ENGINE_INPUT ############
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### END OF SUPERCARD : BEGIN/END ######################################
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This file has been created by helpdoc utility on Fri Mar 01 17:56:50 CET 2019
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