xas
Full name: ase2sprkkr.input_parameters.definitions.xas
Description
XAS task input parameters definition
Description of the sections and parameters
Calculates X-ray absorption spectra
INPUT PARAMETERS xas contains:
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SECTION CONTROL contains:
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DATASET : String The custom field for the description of the problem - the output files will have called 'DATASET.<ext>'.
ADSI : FixedValue(XAS) ≝ XAS Type of the computation.
POTFIL : String The potential file (see SPRKKR documentation for its format). It isn't necessary to set it, it will be set by the calculator.
KRWS : Integer ≝ 1 (optional) If it is 0, RWS is taken from the potential file and scaled. If 1, RWS is calculated by scaling the muffin-tin radii by a common scaling factor. (This setting is forced in the case of FULLPOT.)
KRMT : AnyOf(0,1,2,3,4,5,6) (optional)
Possible values:
0 RMT is taken from the potential file
1 RMT = min( x*RWS )
2 RMT = min( d_ij / 2 )
3 RMT from atomic charge density (=> KRWS=1)
4 RMT from atomic Hartree potential (=> KRWS=1)
5 RMT from total atomic potential (=> KRWS=1)
6 take average of 3 and 4 (=> KRWS=1)
It controls how the muffin-tin radii are calculated.
PRINT : Integer ≝ 0 (optional) Verbosity of the output (0-5). Do not affect the results in any way, just the amount of the printed output.
NONMAG : Flag ≝ False Set this flag, if it is known that the system considered is non-magnetic. This leads to a higher symmetry and a faster calculation.
NOHFF : Flag ≝ False Set this flag, if you want to include hyper fine field calculation. This leads to a slower calculation.
NOSYM : Flag ≝ False Set this flag, if you want to supress all symetry consideration. This leads to a slower calculation.
SECTION TAU contains:
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BZINT : AnyOf(POINTS,WEYL,CLUSTER) (optional)
Possible values:
POINTS special points method
WEYL Weyl method
CLUSTER Cluster method
The Weyl method (BZINT=WEYL) is a point sampling method using more or less ran-
dom points. The number of k-points used for the integration varies quadratically be-
tween 0.0 and ImE according to the imaginary part of the energy.
The special point method (BZINT=POINTS) uses a regular k-point grid with NKTAB
points. It is the standard method and gives a good compromise concerning accuracy
and efficiency. For BZINT=POINTS the parameter NKTAB will be adjusted to allow a
regular mesh.
The mode of BZ-integration used for calculation of the scattering path operator τ
NKTAB : Integer ≝ 250 (optional) Number of points for the special points method
NKTAB2D : Integer (optional) Number of points for the special points method for 2D region of 2D problem
NKTAB3D : Integer (optional) Number of points for the special points method for 3D region of 2D problem
NKMIN : Integer ≝ 300 Minimal number of k-points used for Weyl integration
NKMAX : Integer ≝ 500 Maximal number of k-points used for Weyl integration
KKRMODE : AnyOf(STANDARD-KKR,TB-KKR,LAYER-KKR) (optional)
Expert options:
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CLUSTER : Flag ≝ False (optional, expert) Do cluster type calculation.
NSHLCLU : Integer (optional, expert) Number of atomic shells around the central atom of a cluster
CLURAD : Real (optional, expert) Radius of the cluster in multiples of ALAT.
IQCNTR : Site (optional, expert) The center of the cluster is set at the site position with number IQCNTR of the specified basis.
ITCNTR : AtomicType (optional, expert) The center of the cluster is set at one of the site positions that is occupied by the atomic type ITCNTR.
NLOUT : Integer ≝ 3 (optional, expert) The calculated τ -matrix is printed up to lmax=NLOUT.
MOL : Flag ≝ False (optional, expert) Cluster type calculation but for a molecular system. The system is specified as for CLUSTER.
SECTION ENERGY contains:
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GRID : Array(of Integer) ≝ [6] Type of the grid for the energy-mesh
NE : Array(of Integer) ≝ [180] Number of points in energy-mesh
ImE : Energy (<Real> [Ry|eV]) ≝ 0.01 Ry (optional)
EMIN : Real (optional) The real part of the lowest E-value
EMINEV : Real (optional) EMIN, given in eV with respect to the Fermi level
SECTION TASK contains:
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TASK : FixedValue(XAS) ≝ XAS
IT : Integer ≝ 1 atom type IT
CL : String ≝ 2P initial core level shell
MECHECK : Flag ≝ False (optional)
Expert options:
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OUTPUT : AnyOf(MBARN,SIGMA) ≝ MBARN (optional, expert)
Possible values:
MBARN output of absorption coefficient µas µ atom = µ Vuc in [Mbarn]
SIGMA SIGMA : output as absorptive part of optical conductivity σ = µ c/4π in [10E15/s ]
write extra output
FRAMETET : Real (optional, expert) Polar angle θ (FRAMETET) defining the orientation of the electric field vector of the incident light with respect to the material surface normal. Default is FRAMETET = 0, meaning the field lies along the surface normal.
FRAMEPHI : Real (optional, expert) Azimuthal angle φ (FRAMEPHI) defining the in-plane rotation of the electric field vector of the incident light relative to the surface reference axis. Default is FRAMEPHI = 0, corresponding to alignment with the x-axis of the surface frame.
SECTION SITES contains:
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NL : Array(of Integer) ≝ [3] Angula momentum cutoff (the first discarded l-space)
Expert options:
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SECTION MODE (optional, expert) contains:
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MODE : AnyOf(NREL,SREL,SP-SREL) (optional)
Possible values:
NREL work in the nonrelativistic mode
SREL work in the scalar-relativistic mode
SP-SREL work in the spin-polarized scalar-relativistic mode
Using this option you can switch on the spin polarization and relativistic mode. If its not set (or set to FREL), the full relativity mode is used.
LLOYD : Flag ≝ False Use LLoyd formula for scattering operator. It can improve the accuracy of the Fermi energy.
MDIR : Array(of Real of length 3) (optional, add non-default, array) Common magnetisation direction vector with x, y and z in Cartesian coordinates. The normalisation is arbitrary.
MALF : Real (optional) the (first) angle characterizing the orientation of the magnetic moment direction n.
MBET : Real (optional) the (second) angle characterizing the orientation of the magnetic moment direction n.
MGAM : Real (optional) the (third) angle characterizing the orientation of the magnetic moment direction n.
C : Real ≝ 1.0 (optional, add non-default, array) Scale the speed of light for a given atom type.
SOC : Real ≝ 1.0 (optional, add non-default, array) Scale the strength of the spin-orbit coupling for atom type.
This section contains options that describe, how to consider relativity and/or spin. If the MODE is not specified otherwise the programs of the SPRKKR-package assume that a magnetic system should be treated in a fully relativistic way. By setting the parameter SP-SREL a slightly faster scalar relativistic calculation can be done instead for a magnetic system.
Functions
XAS -xas task input parameters definition |