The CP2K project : input section XAS

Section XAS

Index of all sections. This section is located at __ROOT__%FORCE_EVAL%DFT%XAS.

Sets the method of choice to calculate core-level excitation spectra. The occupied states from which we calculate the excitation should be specified. Localization of the orbitals may be useful. This section can not be repeated and can not be optional.

This section cites following reference: [Iannuzzi2007]

Subsections

Section keywords

Keyword descriptions

_SECTION_PARAMETERS_
&XAS T
controls the activation of core-level spectroscopy simulations
This optional keyword expects a logical
This keyword behaves as a switch T . Default value: F
METHOD
METHOD TP_HH
Method to be used to calculate core-level excitation spectra
This optional keyword expects a keyword. Default value: NONE
valid keywords:
  • NONE: No XAS is calculated
  • TP_HH: Transition potential halfhole
  • TP_FH: Transition potential fullhole
  • TP_VAL: Hole in homo for XES
  • TP_XHH: Transition potential excited halfhole
  • TP_XFH: Transition potential excited fullhole
  • DSCF: DSCF calculations for the first excited state
variants: XAS_METHOD
XES_CORE
XES_CORE 0.5
occupation of the core state in XES calculation by TP_VAL.The homo is emptied by the same amount
This optional keyword expects a real. Default value: 1.0000000000000000E+00
DIPOLE_FORM
DIPOLE_FORM string
Type of integral to get the oscillator strengths in the diipole approximation
This optional keyword expects a keyword. Default value: VELOCITY
valid keywords:
  • LENGTH: Length form
  • VELOCITY: Velocity form
variants: DIP_FORM
SCF_OPTIMIZER
SCF_OPTIMIZER GENERAL
Optimization algorithm: diagonalization or OT
This optional keyword expects a keyword. Default value: GENERAL
valid keywords:
  • DEFAULT: same as in std SCF
  • GENERAL: diagonalization
MAXSTEP
MAXSTEP 150
Max # of steps in the cls-scf for one excitation
This optional keyword expects an integer. Default value: 150
CONVERGENCE
CONVERGENCE 0.00005
Convergence criterion for the xas-scf
This optional keyword expects a real. Default value: 4.9999999999999998E-07
variants: CONV
EPS_DIIS
EPS_DIIS 0.5
treshold on the convergence to start using DIAG/DIIS for the cls-scfif default, the scf_control value is used
This optional keyword expects a real. Default value: -1.0000000000000000E+00
MIXING
MIXING 0.5
fraction of new density to be mixed in the xas-scf,if default, the scf_control value is used
This optional keyword expects a real. Default value: -1.0000000000000000E+00
STATE_TYPE
STATE_TYPE 1S
Type of the orbitas that are excited for the xas spectra calculation
This optional keyword expects a keyword. Default value: 1S
valid keywords:
  • 1S: 1s orbitals
  • 2S: 2s orbitals
  • 2P: 2p orbitals
variants: TYPE
STATE_SEARCH
STATE_SEARCH 1
# of states where to look for the one to be excited
This optional keyword expects an integer. Default value: -1
SMEAR
SMEAR 0.5
smearing coefficient
This optional keyword expects a real. Default value: 0.0000000000000000E+00
ATOMS_LU_BOUNDS
ATOMS_LU_BOUNDS integer integer
The lower and upper index of the atoms to be excited
This optional keyword expects precisely 2 integers. Default value: 0 0
variants: AT_LU
ATOMS_LIST
ATOMS_LIST 1 2
Indexes of the atoms to be excitedThis keyword can be repeated several times(useful if you have to specify many indexes).
This optional keyword expects a list of integers, and may repeat
variants: AT_LIST
ADDED_MOS
ADDED_MOS {integer}
Number of additional MOS added spin up only
This optional keyword expects an integer. Default value: -1
MAX_ITER_ADDED
MAX_ITER_ADDED 100
maximum number of iteration in calculation of added orbitals
This optional keyword expects an integer. Default value: 2999
EPS_ADDED
EPS_ADDED 1.e-6
target accuracy incalculation of the added orbitals
This optional keyword expects a real. Default value: 1.0000000000000001E-05
NGAUSS
NGAUSS {integer}
Number of gto's for the expansion of the stoof the type given by STATE_TYPE
This optional keyword expects an integer. Default value: 3
EMISSION
EMISSION
Calculate also the emission spectrum
This optional keyword expects a logical
This keyword behaves as a switch T . Default value: F
RESTART
RESTART
Restart the excited state if the restart file exists
This optional keyword expects a logical
This keyword behaves as a switch T . Default value: F
WFN_RESTART_FILE_NAME
WFN_RESTART_FILE_NAME
Root of the file names where to read the MOS fromwhich to restart the calculation of the core level excited states
This optional keyword expects a string
variants: RESTART_FILE_NAME


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