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Section REAL_TIME_PROPAGATION

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

Parameters needed to set up the real time propagation for the electron dynamics. This section can not be repeated and can be optional.

Subsections

Section keywords

Keyword descriptions

MAX_ITER
MAX_ITER 10
Maximal number of iterations for the self consistent propagator loop.
This optional keyword expects an integer. Default value: 10
EPS_ITER
EPS_ITER 1.0E-5
Convergence criterium for the self consistent propagator loop.
This optional keyword expects a real. Default value: 9.9999999999999995E-07
ASPC_ORDER
ASPC_ORDER 4
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 expects an integer. Default value: 4
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 expects a keyword. Default value: TAYLOR
valid keywords:
  • TAYLOR: exponential is evaluated using scaling and squaring in combination with a taylor expansion of the exponential.
  • DIAG: uses the eignvalues an eigenvectors to calculate the exponential.
  • PADE: uses scaling and squaring together with the pade approximation
  • ARNOLDI: uses arnoldi subspace algorithm to compute exp(H)*MO directly, can't be used in combination with Crank Nicholson
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 expects a real. Default value: 1.0000000000000001E-09
PROPAGATOR
PROPAGATOR ETRS
Which propagator should be used for the orbitals
This optional keyword expects a keyword. Default value: ETRS
valid keywords:
  • ETRS: enforced time reversible symmetry
  • CN: Crank Nicholson propagator
  • EM: Exponential midpoint propagator
INITIAL_WFN
INITIAL_WFN SCF_WFN
Controls the initial WFN used for propagation.
This optional keyword expects a keyword. Default value: SCF_WFN
valid keywords:
  • SCF_WFN: An SCF run is performed to get the initial state.
  • 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


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