Section XAS_TDP

• XAS simulations using linear-response TDDFT. Excitation from specified core orbitals are considered one at a time. In case of high symmetry structures, donor core orbitals should be localized.

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / XAS_TDP

• This section cannot be repeated.

• Subsections

  • DONOR_STATES
  • GW2X
  • KERNEL
  • OT_SOLVER
  • PRINT

• Keywords

  • SECTION_PARAMETERS
  • CHECK_ONLY
  • DIPOLE_FORM
  • ENERGY_RANGE
  • EPS_FILTER
  • EPS_PGF_XAS
  • EXCITATIONS
  • GRID
  • N_EXCITED
  • QUADRUPOLE
  • RESTART_FROM_FILE
  • SPIN_ORBIT_COUPLING
  • TAMM_DANCOFF

• Keyword descriptions

  SECTION_PARAMETERS
  	&XAS_TDP {Logical}
  	controls the activation of XAS simulations with linear response TDDFT.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  CHECK_ONLY
  	CHECK_ONLY {Logical}
  	This keyword defines whether the full calculation should be done or not. If set to .TRUE., only the determination of donor MOs is conducted. This run option allows for cheap verification of the input parameters
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  DIPOLE_FORM
  	DIPOLE_FORM {Keyword}
  	Type of integral to get the oscillator strengths in the dipole approximation
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: VELOCITY
  	List of valid keywords: LENGTH Length form 〈 0 | e r | n 〉 VELOCITY Velocity form 〈 0 | d/dr | n 〉
  	Alias names for this keyword: DIP_FORM

  ENERGY_RANGE
  	ENERGY_RANGE {Real}
  	The energy range in eV for which excitations are considered. Only excitated states within the range of: first excitation energy + ENERGY_RANGE are kept. If ENERGY_RANGE and N_EXCITED are specified, the former has priority. Negative values are ignored and N_EXCITED takes over.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: -1.00000000E+000
  	Alias names for this keyword: E_RANGE

  EPS_FILTER
  	EPS_FILTER {Real}
  	The threshold used for sparse matrix operations
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-010
  	Alias names for this keyword: EPS_FILTER_MATRIX

  EPS_PGF_XAS
  	EPS_PGF_XAS {Real}
  	The threshold used to determine the spacial extent of all primitive Gaussian functions used for the construction of neighbor lists in the XAS_TDP method. By default, takes the value of QS%EPS_PGF_ORB. Useful if the former value is tiny due to possible ground state HFX contributions.
  	This keyword cannot be repeated and it expects precisely one real.
  	Alias names for this keyword: EPS_PGF, EPS_PGF_XAS_TDP

  EXCITATIONS
  	EXCITATIONS {Keyword}
  	Specify the type of excitation to consider. In case of a resctricted closed-shell ground state calculation, RCS_SINGLET or/and RCS_TRIPLET can be chosen. In case of a open-shell ground state calculation (either UKS or ROKS), standard spin conserving excitation (OS_SPIN_CONS) or/and spin-flip excitation (OS_SPIN_FLIP) can be chosen.
  	This keyword can be repeated and it expects precisely one keyword.
  	Default value: RCS_SINGLET
  	List of valid keywords: OS_SPIN_CONS Spin-conserving excitations on top of open-shell ground state OS_SPIN_FLIP Spin-flip excitation on top of open-shell ground state RCS_SINGLET Singlet excitation on top of restricted closed-shell ground state RCS_TRIPLET Triplet excitation on top of restricted closed-shell ground state
  	Alias names for this keyword: EXCITATION

  GRID
  	GRID {Word} {Word} {Word}
  	Specification of the atomic angular and radial grids for a given atomic kind. This keyword can/should be repeated for each excited kind. The default grid dimensions are those set for the GAPW ground state calculation. These grids are used for the xc-kernel integration. Usage: GRID < KIND > < LEBEDEV_GRID > < RADIAL_GRID >
  	This keyword can be repeated and it expects precisely 3 words.
  	Alias names for this keyword: ATOMIC_GRID

  N_EXCITED
  	N_EXCITED {Integer}
  	The number of excited states to compute per donor molecular orbital. (e.g. if 2p excitations, 3*N_EXCITED excited states are considered). If N_EXCITED is set to -1, all excitations are considered
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: -1
  	Alias names for this keyword: N_ROOTS

  QUADRUPOLE
  	QUADRUPOLE {Logical}
  	Compute the electric quadrupole contribution to the oscillator strenghts (in the length representation with the origin set on the relevant excited atom)
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.
  	Alias names for this keyword: DO_QUADRUPOLE, DO_QUAD, QUAD

  RESTART_FROM_FILE
  	RESTART_FROM_FILE {Word} ...
  	By providing a RESTART file containing the linear-response orbitals and excitations energies from a previous calculation, all computations are skipped except for the corresponding PDOS and/or CUBE file printing as defined in the PRINT subsection. Basis sets and geometry need to be consistent.
  	This keyword cannot be repeated and it expects a list of words.
  	Alias names for this keyword: RESTART_FILENAME, RST_FILENAME, RESTART_FILE, RST_FILE

  SPIN_ORBIT_COUPLING
  	SPIN_ORBIT_COUPLING {Logical}
  	Whether spin-orbit coupling should be added. Note: only applies for spin-restricted calculations with singlet and triplet excitations OR spin-unrestricted calculations with both spin-conserving and spin-flip.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.
  	Alias names for this keyword: SOC

  TAMM_DANCOFF
  	TAMM_DANCOFF {Logical}
  	Whether the Tamm-Dancoff approximation should be used.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .TRUE.
  	Alias names for this keyword: TDA