Section 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.

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / XAS

• This section cannot be repeated and cannot be optional.

• This section cites the following reference: [Iannuzzi2007]

• Subsections

  • LOCALIZE
  • MIXING
  • PRINT
  • SMEAR

• Keywords

  • SECTION_PARAMETERS
  • ADDED_MOS
  • ATOMS_LIST
  • CONVERGENCE
  • DIPOLE_FORM
  • EPS_ADDED
  • EPS_DIIS
  • MAXSTEP
  • MAX_ITER_ADDED
  • METHOD
  • NGAUSS
  • RESTART
  • SCF_OPTIMIZER
  • STATE_SEARCH
  • STATE_TYPE
  • WFN_RESTART_FILE_NAME
  • XES_CORE

• Keyword descriptions

  SECTION_PARAMETERS
  	&XAS T
  	controls the activation of core-level spectroscopy simulations
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  ADDED_MOS
  	ADDED_MOS {INTEGER}
  	Number of additional MOS added spin up only
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: -1

  ATOMS_LIST
  	ATOMS_LIST {INTEGER} {INTEGER} .. {INTEGER}
  	Indexes of the atoms to be excitedThis keyword can be repeated several times(useful if you have to specify many indexes).
  	This required keyword can be repeated and it expects a list of integers.
  	Alias names for this keyword: AT_LIST

  CONVERGENCE
  	CONVERGENCE 0.00005
  	Convergence criterion for the xas-scf
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 5.00000000E-07
  	Alias names for this keyword: CONV

  DIPOLE_FORM
  	DIPOLE_FORM STRING
  	Type of integral to get the oscillator strengths in the diipole approximation
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: VELOCITY
  	List of valid keywords: LENGTH Length form <i|e r |j> VELOCITY Velocity form <i|d/dr|j>
  	Alias names for this keyword: DIP_FORM

  EPS_ADDED
  	EPS_ADDED 1.E-6
  	target accuracy incalculation of the added orbitals
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-05

  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 cannot be repeated and it expects precisely one real.
  	Default value: -1.00000000E+00

  MAXSTEP
  	MAXSTEP 150
  	Max # of steps in the cls-scf for one excitation
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 150

  MAX_ITER_ADDED
  	MAX_ITER_ADDED 100
  	maximum number of iteration in calculation of added orbitals
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 2999

  METHOD
  	METHOD TP_HH
  	Method to be used to calculate core-level excitation spectra
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NONE
  	List of valid keywords: DSCF DSCF calculations to compute the first (core)excited state NONE No core electron spectroscopy TP_FH Transition potential full-hole TP_HH Transition potential half-hole TP_VAL Hole in homo for X-ray emission only TP_XFH Transition potential excited full-hole TP_XHH Transition potential excited half-hole
  	Alias names for this keyword: XAS_METHOD

  NGAUSS
  	NGAUSS {INTEGER}
  	Number of gto's for the expansion of the stoof the type given by STATE_TYPE
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3

  RESTART
  	RESTART
  	Restart the excited state if the restart file exists
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  SCF_OPTIMIZER
  	SCF_OPTIMIZER GENERAL
  	Optimization algorithm: diagonalization or OT
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: GENERAL
  	List of valid keywords: DEFAULT same as in std SCF GENERAL diagonalization

  STATE_SEARCH
  	STATE_SEARCH 1
  	# of states where to look for the one to be excited
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: -1

  STATE_TYPE
  	STATE_TYPE 1S
  	Type of the orbitas that are excited for the xas spectra calculation
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: 1S
  	List of valid keywords: 1S 1s orbitals 2P 2p orbitals 2S 2s orbitals
  	Alias names for this keyword: TYPE

  WFN_RESTART_FILE_NAME
  	WFN_RESTART_FILE_NAME <FILENAME>
  	Root of the file names where to read the MOS fromwhich to restart the calculation of the core level excited states
  	This optional keyword cannot be repeated and it expects precisely one string.
  	Alias names for this keyword: RESTART_FILE_NAME

  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 cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E+00