A
Name ABCapHeight
Section Time-Dependent::Absorbing Boundaries
Type float
Default -0.2 a.u.
When AbsorbingBoundaries = cap, this is the height of the imaginary potential.
Name ABShape
Section Time-Dependent::Absorbing Boundaries
Type block
Set the shape of the absorbing boundaries. Here you can set the inner
and outer bounds by setting the block as follows:
%ABShape
inner | outer | "user-defined"
%
The optional 3rd column is a user-defined expression for the absorbing
boundaries. For example, $r$ creates a spherical absorbing zone for
coordinates with ${\tt inner} < r < {\tt outer}$, and $z$ creates an
absorbing plane.
Note, values outer larger than the box size may lead in these cases to
unexpected reflection behaviours.
If no expression is given, the absorbing zone follows the edges of the
box (not valid for user-defined box).
Name AbsorbingBoundaries
Section Time-Dependent::Absorbing Boundaries
Type flag
Default not_absorbing
To improve the quality of the spectra by avoiding the formation of
standing density waves, one can make the boundaries of the simulation
box absorbing and use exterior complex scaling.
Options:
- not_absorbing:
Reflecting boundaries.
- mask:
Absorbing boundaries with a mask function.
- cap:
Absorbing boundaries with a complex absorbing potential.
- exterior:
Exterior complex scaling (not yet implemented).
Name ABWidth
Section Time-Dependent::Absorbing Boundaries
Type float
Specifies the boundary width. For a finer control over the absorbing boundary
shape use ABShape.
Name ACBN0IntersiteCutoff
Section Hamiltonian::DFT+U
Type float
The cutoff radius defining the maximal intersite distance considered.
Only available with ACBN0 functional with intersite interaction.
Name ACBN0IntersiteInteraction
Section Hamiltonian::DFT+U
Type logical
Default no
If set to yes, Octopus will determine the effective intersite interaction V
Only available with ACBN0 functional.
It is strongly recommended to set AOLoewdin=yes when using the option.
Name ACBN0RotationallyInvariant
Section Hamiltonian::DFT+U
Type logical
If set to yes, Octopus will use for U and J a formula which is rotationally invariant.
This is different from the original formula for U and J.
This is activated by default, except in the case of spinors, as this is not yet implemented in this case.
Name ACBN0Screening
Section Hamiltonian::DFT+U
Type float
Default 1.0
If set to 0, no screening will be included in the ACBN0 functional, and the U
will be estimated from bare Hartree-Fock. If set to 1 (default), the full screening
of the U, as defined in the ACBN0 functional, is used.
Name AccelBenchmark
Section Execution::Accel
Type logical
Default no
If this variable is set to yes, Octopus will run some
routines to benchmark the performance of the accelerator device.
Name AccelDevice
Section Execution::Accel
Type integer
Default gpu
This variable selects the OpenCL or CUDA accelerator device
that Octopus will use. You can specify one of the options below
or a numerical id to select a specific device.
Values >= 0 select the device to be used. In case of MPI enabled runs
devices are distributed in a round robin fashion, starting at this value.
Options:
- gpu:
If available, Octopus will use a GPU.
- cpu:
If available, Octopus will use a CPU (only for OpenCL).
- accelerator:
If available, Octopus will use an accelerator (only for OpenCL).
- accel_default:
Octopus will use the default device specified by the implementation.
implementation.
Name AccelPlatform
Section Execution::Accel
Type integer
Default 0
This variable selects the OpenCL platform that Octopus will
use. You can give an explicit platform number or use one of
the options that select a particular vendor
implementation. Platform 0 is used by default.
This variable has no effect for CUDA.
Options:
- amd:
Use the AMD OpenCL platform.
- nvidia:
Use the Nvidia OpenCL platform.
- ati:
Use the ATI (old AMD) OpenCL platform.
- intel:
Use the Intel OpenCL platform.
Name AdaptivelyCompressedExchange
Section Hamiltonian
Type logical
Default false
(Experimental) If set to yes, Octopus will use the adaptively compressed exchange
operator (ACE) for HF and hybrid calculations, as defined in
Lin, J. Chem. Theory Comput. 2016, 12, 2242.
Name AllElectronANCParam
Section System::Species
Type integer
Default 4
Default values for the parameter anc_a. This is usefull
for specifying multiple atoms without specifying the species block.
Name AllElectronSigma
Section System::Species
Type integer
Default 0.6
Default value for the parameter gaussian_width. This is useful
for specifying multiple atoms without specifying the species block. The
default value is taken from the recommendation in
Phys. Rev. B 55, 10289 (1997).
Name AllElectronType
Section System::Species
Type integer
Default no
Selects the type of all-electron species that applies by default to all
atoms. This is not compatible with PseudopotentialSet, but it is
compatible with the Species block.
Options:
- no:
Do not specify any default all-electron type of species. All species must be
specified in the Species block.
- full_delta:
All atoms are supposed to be by default of type species_full_delta.
- full_gaussian:
All atoms are supposed to be by default of type species_full_gaussian.
- full_anc:
All atoms are supposed to be by default of type species_full_anc.
Name AllowCPUonly
Section Execution::Accel
Type logical
In order to prevent waste of resources, the code will normally stop when the GPU is disabled due to
incomplete implementations or incompatibilities. AllowCPUonly = yes overrides this and allows the
code execution also in these cases.
Name AnalyticalExternalSource
Section Maxwell
Type logical
Default no
This means the analytical evaluation of formula will be used, Maxwell propagation will not be used.
Name AnimationMultiFiles
Section Utilities::oct-xyz-anim
Type logical
Default false
If true, each iteration written will be in a separate file.
Name AnimationSampling
Section Utilities::oct-xyz-anim
Type integer
Default 100
Sampling rate of the animation. The animation will be constructed using
the iteration numbers that are multiples of AnimationSampling.
Name AOCombineJOrbitals
Section Atomic Orbitals
Type logical
Default no
By default, Octopus creates two sets of atomic orbitals for j-dependent pseudopotentials.
When doing ACBN0 functional, this leads to a Hubbard U for j=l-1/2 and one for j=l+1/2, unless
hubbard_j is specified in the species block.
By setting this variable to yes, one can instead define a single set of atomic orbitals that
contains both the j=l-1/2 and j=l+1/2 orbitals.
This is only relevant for spinor calculations with j-dependent pseudopotentials.
Name AOLoewdin
Section Atomic Orbitals
Type logical
Default no
This option determines if the atomic orbital basis is orthogonalized or not.
This is done for using the Loewdin orthogonalization scheme.
The default is set to no for the moment as this option is
not yet implemented for isolated systems, and seems to lead to important egg-box effect
Name AONormalize
Section Atomic Orbitals
Type logical
Default yes
If set to yes, Octopus will normalize the atomic orbitals individually.
This variable is ignored is AOLoewdin is set to yes.
Name AOSubmesh
Section Atomic Orbitals
Type logical
If set to yes, Octopus will use submeshes to internally store the orbitals with
their phase instead of storing them on the mesh. This is usually slower for small
periodic systems, but becomes advantageous for large supercells.
Submeshes are not compatible with Loewdin orthogonalization.
For periodic systems, the default is set to no, whereas it is set to yes for isolated systems.
Name AOThreshold
Section Atomic Orbitals
Type float
Default 0.01
Determines the threshold used to compute the radius of the atomic orbitals for DFT+U and for Wannier90.
This radius is computed by making sure that the
absolute value of the radial part of the atomic orbital is below the specified threshold.
This value should be converged to be sure that results do not depend on this value.
However increasing this value increases the number of grid points covered by the orbitals and directly affect performances.
Name AOTruncation
Section Atomic Orbitals
Type flag
Default ao_full
This option determines how Octopus will truncate the orbitals used for DFT+U.
Except for the full method, the other options are only there to get a quick idea.
Options:
- ao_full:
The full size of the orbitals used. The radius is controled by variable AOThreshold.
- ao_box:
The radius of the orbitals are restricted to the size of the simulation box.
This reduces the number of points used to discretize the orbitals.
This is mostly a debug option, and one should be aware that changing the size of the simulation box
will affect the result of the calculation. It is recommended to use ao_nlradius instead.
- ao_nlradius:
The radius of the orbitals are restricted to the radius of the non-local part of the pseudopotential
of the corresponding atom.
Name ArnoldiOrthogonalization
Section Time-Dependent::Propagation
Type integer
The orthogonalization method used for the Arnoldi procedure.
Only for TDExponentialMethod = lanczos.
Options:
- cgs:
Classical Gram-Schmidt (CGS) orthogonalization.
The algorithm is defined in Giraud et al., Computers and Mathematics with Applications 50, 1069 (2005).
- drcgs:
Classical Gram-Schmidt orthogonalization with double-step reorthogonalization.
The algorithm is taken from Giraud et al., Computers and Mathematics with Applications 50, 1069 (2005).
According to this reference, this is much more precise than CGS or MGS algorithms.
Name AtomsMagnetDirection
Section SCF::LCAO
Type block
This option is only used when GuessMagnetDensity is
set to user_defined. It provides a direction for the
magnetization vector of each atom when building the guess
density. In order to do that, the user should specify the
coordinates of a vector that has the desired direction and
norm. Note that it is necessary to maintain the ordering in
which the species were defined in the coordinates
specifications.
For spin-polarized calculations, the vectors should have only
one component; for non-collinear-spin calculations, they
should have three components. If the norm of the vector is greater
than the number of valence electrons in the atom, it will be rescaled
to this number, which is the maximum possible magnetization.
Name AxisType
Section Utilities::oct-center-geom
Type integer
Default inertia
After the structure is centered, it is also aligned to a set of orthogonal axes.
This variable decides which set of axes to use. Only implemented for 3D, in which case
the default is inertia; otherwise none is default and the only legal value.
Options:
- none:
Do not rotate. Will still give output regarding center of mass and moment of inertia.
- inertia:
The axis of inertia.
- pseudo_inertia:
Pseudo-axis of inertia, calculated considering all species to have equal mass.
- large_axis:
The larger axis of the molecule.