B

Name BandStructureComputeProjections
Section Output
Type logical
Default false

Determines if projections of wavefunctions on the atomic orbitals are computed or not for obtaining the orbital resolved band-structure.

Name BerkeleyGW_CalcDipoleMtxels
Section Output::BerkeleyGW
Type logical
Default false

Whether to calculate dipole matrix elements, to be written in vmtxel. This should be done when calculating WFN_fi for Bethe-Salpeter calculations with light polarization in a finite direction. In that case, a shifted grid WFNq_fi cannot be calculated, but we can instead use matrix elements of $r$ in a more exact scheme. In absorption.inp, set read_vmtxel and use_momentum. Specify the number of conduction and valence bands you will use in BSE here with BerkeleyGW_VmtxelNumCondBands and BerkeleyGW_VmtxelNumValBands.

Name BerkeleyGW_CalcExchange
Section Output::BerkeleyGW
Type logical
Default false

Whether to calculate exchange matrix elements, to be written in x.dat. These will be calculated anyway by BerkeleyGW Sigma, so this is useful mainly for comparison and testing.

Name BerkeleyGW_Complex
Section Output::BerkeleyGW
Type logical
Default false

! Even when wavefunctions, density, and XC potential could be real in reciprocal space, ! they will be output as complex.

Name BerkeleyGW_NumberBands
Section Output::BerkeleyGW
Type integer
Default all states

Wavefunctions for bands up to this number will be output. Must be between <= number of states. If < 1, no wavefunction file will be output.

Name BerkeleyGW_VmtxelNumCondBands
Section Output::BerkeleyGW
Type integer
Default 0

Number of conduction bands for which to calculate vmtxel, if you have set BerkeleyGW_CalcDipoleMtxels = yes. This should be equal to the number to be used in BSE.

Name BerkeleyGW_VmtxelNumValBands
Section Output::BerkeleyGW
Type integer
Default 0

Number of valence bands for which to calculate vmtxel, if you have set BerkeleyGW_CalcDipoleMtxels = yes. This should be equal to the number to be used in BSE.

Name BerkeleyGW_VmtxelPolarization
Section Output::BerkeleyGW
Type block
Default (1, 0, 0)

Polarization, i.e. direction vector, for which to calculate vmtxel, if you have set BerkeleyGW_CalcDipoleMtxels = yes. May not have any component in a periodic direction. The vector will be normalized.

Name BerkeleyGW_Vxc_diag_nmax
Section Output::BerkeleyGW
Type integer
Default nst

Highest band for which to write diagonal exchange-correlation matrix elements. Must be between <= number of states. If < 1, diagonals will be skipped.

Name BerkeleyGW_Vxc_diag_nmin
Section Output::BerkeleyGW
Type integer
Default 1

Lowest band for which to write diagonal exchange-correlation matrix elements. Must be <= number of states. If < 1, diagonals will be skipped.

Name BerkeleyGW_Vxc_offdiag_nmax
Section Output::BerkeleyGW
Type integer
Default nst

Highest band for which to write off-diagonal exchange-correlation matrix elements. Must be <= number of states. If < 1, off-diagonals will be skipped.

Name BerkeleyGW_Vxc_offdiag_nmin
Section Output::BerkeleyGW
Type integer
Default 1

Lowest band for which to write off-diagonal exchange-correlation matrix elements. Must be <= number of states. If < 1, off-diagonals will be skipped.

Name BerkeleyGW_WFN_filename
Section Output::BerkeleyGW
Type string
Default WFN

Filename for the wavefunctions.

Name BesselBeamAxisShift
Section Maxwell
Type block

The BesselBeamAxisShift block allows to shift the Bessel Beam, which is centered at (0,0,0) as default. Selected position point will be used as the new center of the Bessel Beam. When defining a BesselBeamAxisShift, please make sure to define a shift for each Bessel source you use, then it is possible to tell which source is shifted according to which BesselShift, respectively. %BesselBeamAxisShift
   0.0 | 2.0 | 5.0
%

Name BornChargeSumRuleCorrection
Section Linear Response::Polarizabilities
Type logical
Default true

Enforce the acoustic sum rule by distributing the excess sum of Born charges equally among the atoms. Sum rule: $\sum_{\alpha} Z^{*}_{\alpha, i, j} = Z_{\rm tot} \delta_{ij}$. Violation of the sum rule may be caused by inadequate spacing, box size (in finite directions), or k-point sampling (in periodic directions).

Name BoxCenter
Section Mesh::Simulation Box
Type float

This block defines the coordinate center of the simulation box

Name BoxCgalFile
Section Mesh::Simulation Box
Type string

Filename to be read in by the cgal library. It should describe a shape that is used for the simulation box

Name BoxShape
Section Mesh::Simulation Box
Type integer

This variable decides the shape of the simulation box. The default is minimum for finite systems and parallelepiped for periodic systems. Note that some incompatibilities apply:

• Spherical or minimum mesh is not allowed for periodic systems.
• Cylindrical mesh is not allowed for systems that are periodic in more than one dimension.
• box_image is only allowed in 2D.

• sphere:
  The simulation box will be a sphere of radius Radius. (In 2D, this is a circle.)
  
• cylinder:
  The simulation box will be a cylinder with radius Radius and height (in the x-direction) of 2 Xlength.
  
• minimum:
  The simulation box will be constructed by adding spheres created around each atom (or user-defined potential), of radius Radius.
  
• parallelepiped:
  The simulation box will be a parallelepiped whose dimensions are taken from the variable Lsize.
  
• box_image:
  The simulation box will be defined through an image, specified with BoxShapeImage. White (RGB = 255,255,255) means that the point is contained in the simulation box, while any other color means that the point is out. The image will be scaled to fit Lsize, while its resolution will define the default Spacing. The actual box may be slightly larger than Lsize to ensure one grid point = one pixel for default Spacing.
  
• box_cgal:
  The simulation box will be defined by a file read using the CGAL library. The file name needs to be specified with BoxCgalFile. Lsize needs to be large enough to contain the shape defined in the file.
  
• user_defined:
  The shape of the simulation box will be read from the variable BoxShapeUsDef.
  

Name BoxShapeImage
Section Mesh::Simulation Box
Type string

Name of the file that contains the image that defines the simulation box when BoxShape = box_image. No default. Will search in current directory and OCTOPUS-HOME/share/.

Name BoxShapeUsDef
Section Mesh::Simulation Box
Type string

Boolean expression that defines the interior of the simulation box. For example, BoxShapeUsDef = "(sqrt(x^2+y^2) <= 4) && z>-2 && z<2" defines a cylinder with axis parallel to the z-axis.