Section REAL_TIME_PROPAGATION

• Parameters needed to set up the real time propagation for the electron dynamics

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / REAL_TIME_PROPAGATION

• This section cannot be repeated and can be optional.

• This section cites the following reference: [Kunert2003]

• Subsections

  • PRINT

• Keywords

  • ASPC_ORDER
  • EPS_ITER
  • EXP_ACCURACY
  • EXTRAPOLATION
  • HFX_BALANCE_IN_CORE
  • INITIAL_WFN
  • MAT_EXP
  • MAX_ITER
  • PROPAGATOR
  • SC_CHECK_START

• Keyword descriptions

  ASPC_ORDER
  	ASPC_ORDER 3
  	Speciefies how many steps will be used for extrapolation. One will be always used which is means X(t+dt)=X(t)
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3

  EPS_ITER
  	EPS_ITER 1.0E-5
  	Convergence criterium for the self consistent propagator loop.
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-07

  EXP_ACCURACY
  	EXP_ACCURACY 1.0E-6
  	Accuracy for the taylor and pade approximation. This is only an upper bound bound since the norm used for the guess is an upper bound for the needed one.
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-09

  EXTRAPOLATION
  	EXTRAPOLATION MOS
  	Controls which quantity is extrapolated
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: MOS
  	List of valid keywords: MOS Direct extrapolation on the MO matrices S_KS Extrapolation on the Kohn-Sham matrix, resp. the exponential in case of ETRS

  HFX_BALANCE_IN_CORE
  	HFX_BALANCE_IN_CORE
  	If HFX is used, this keyword forces a redistribution/recalculation of the integrals, balanced with respect to the in core steps.
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  INITIAL_WFN
  	INITIAL_WFN SCF_WFN
  	Controls the initial WFN used for propagation.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: SCF_WFN
  	List of valid keywords: RESTART_WFN A wavefunction from a previous scf is propageted. Especially useful, if electronic constraints or restraints are used in the previous calculation, since these do not work in the rtp scheme. RT_RESTART use the wavefunction of a real time propagation/ehrenfest run SCF_WFN An SCF run is performed to get the initial state.

  MAT_EXP
  	MAT_EXP TAYLOR
  	Which method should be used to calculate the exponential in the propagator. For Ehrenfest MD only the Taylor method works, for real time propagation diagonalization works as well.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: ARNOLDI
  	List of valid keywords: ARNOLDI uses arnoldi subspace algorithm to compute exp(H)*MO directly, can't be used in combination with Crank Nicholson DIAG uses the eignvalues an eigenvectors to calculate the exponential. PADE uses scaling and squaring together with the pade approximation TAYLOR exponential is evaluated using scaling and squaring in combination with a taylor expansion of the exponential.

  MAX_ITER
  	MAX_ITER 10
  	Maximal number of iterations for the self consistent propagator loop.
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 10

  PROPAGATOR
  	PROPAGATOR ETRS
  	Which propagator should be used for the orbitals
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: ETRS
  	List of valid keywords: CN Crank Nicholson propagator EM Exponential midpoint propagator ETRS enforced time reversible symmetry

  SC_CHECK_START
  	SC_CHECK_START 3
  	Speciefies how many iteration steps will be done without a check for self consistency. Can save some time in big calculations.
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0