CP2K Open Source Molecular Dynamics

Input file for real time propagation of formaldehyde.

This file will excite the formaldehyde using an impulse (delta kick) then propagate the system in time.

The file ch2o_pbe_rtp-output-moments.dat should contain the system dipole moment at each time step.

By extracting the z component of this moment and taking a discrete fourier transform of it (xmgrace maybe) you should be able to obtain the optical absorption spectrum of formaldehyde at PBE level.

input.inp

&GLOBAL
  PROJECT ch2o_pbe_rtp
  RUN_TYPE rt_propagation
  PRINT_LEVEL low
&END GLOBAL
 
&FORCE_EVAL
  METHOD Quickstep
 
  &DFT
    BASIS_SET_FILE_NAME GTH_BASIS_SETS
    POTENTIAL_FILE_NAME POTENTIAL
 
    &MGRID
      CUTOFF 400
    &END MGRID
 
    &QS
      METHOD gpw
    &END QS
 
    &SCF
      MAX_SCF   30
      EPS_SCF   1e-7
      SCF_GUESS atomic
    &END SCF
 
    &POISSON
       PERIODIC none
       POISSON_SOLVER wavelet
    &END POISSON
 
    &XC
      &XC_FUNCTIONAL pbe
      &END XC_FUNCTIONAL
    &END XC
 
       &REAL_TIME_PROPAGATION
      INITIAL_WFN SCF_WFN
      EXP_ACCURACY 1E-15
      EPS_ITER 1E-5
      MAX_ITER 100
      DELTA_PULSE_DIRECTION 0 0 1
 
    &END REAL_TIME_PROPAGATION
 
    &PRINT
      &MOMENTS LOW
         ADD_LAST NUMERIC
         FILENAME output
         PERIODIC .FALSE.
         COMMON_ITERATION_LEVELS 5
      &END MOMENTS
      &MULLIKEN MEDIUM
      &END MULLIKEN
    &END PRINT
 
  &END DFT
 
  &SUBSYS
    &TOPOLOGY
       &CENTER_COORDINATES
       &END CENTER_COORDINATES
    &END TOPOLOGY
 
    &CELL
      ABC 9.0 9.0 9.0
      PERIODIC NONE
    &END CELL
 
    &COORD
  O         0.094933   -0.000368    0.895642
  C        -0.031077   -0.000121   -0.307326
  H        -0.090437    0.947608   -0.895642
  H        -0.094933   -0.947608   -0.895562
    &END COORD
 
        &KIND O
      BASIS_SET aug-TZV2P-GTH
      POTENTIAL GTH-PBE-q6
    &END KIND
    &KIND C
      BASIS_SET aug-TZV2P-GTH
      POTENTIAL GTH-PBE-q4
    &END KIND
    &KIND H
      BASIS_SET aug-TZV2P-GTH
      POTENTIAL GTH-PBE-q1
    &END KIND
  &END SUBSYS
&END FORCE_EVAL
 
&MOTION
  &MD
    ENSEMBLE NVE
    STEPS 20000
    TIMESTEP 0.025
    TEMPERATURE 300.0
  &END MD
&END MOTION

Here is an input that calculates the first five excited states of formaldehyde using TDDFPT instead. The energies should be the same as for RTP.

Note that this needs a very up to date CP2K executable to work version > r17219

input_tddfpt.inp

PROJECT ch2o_pbe_rks_s_tddfpt
  RUN_TYPE energy
  PRINT_LEVEL low
&END GLOBAL
 
&FORCE_EVAL
  METHOD Quickstep
 
  &PROPERTIES
    &TDDFPT
       NSTATES      5
       MAX_ITER    10
       CONVERGENCE [eV] 1.0e-3
    &END TDDFPT
  &END PROPERTIES
 
  &DFT
    BASIS_SET_FILE_NAME GTH_BASIS_SETS
    POTENTIAL_FILE_NAME POTENTIAL
 
    &MGRID
      CUTOFF 400
    &END MGRID
 
    &QS
      METHOD gpw
    &END QS
 
    &SCF
      MAX_SCF   30
      EPS_SCF   1e-7
      SCF_GUESS atomic
    &END SCF
 
    &POISSON
       PERIODIC none
       POISSON_SOLVER wavelet
    &END POISSON
 
    &XC
      &XC_FUNCTIONAL pbe
      &END XC_FUNCTIONAL
 
      &XC_GRID
        XC_DERIV SPLINE2_SMOOTH
      &END XC_GRID
    &END XC
  &END DFT
 
  &SUBSYS
    &TOPOLOGY
       &CENTER_COORDINATES
       &END CENTER_COORDINATES
    &END TOPOLOGY
 
    &CELL
      ABC 9.0 9.0 9.0
      PERIODIC NONE
    &END CELL
 
    &COORD
  O         0.094933   -0.000368    0.895642
  C        -0.031077   -0.000121   -0.307326
  H        -0.090437    0.947608   -0.895642
  H        -0.094933   -0.947608   -0.895562
    &END COORD
 
    &KIND O
      BASIS_SET aug-TZV2P-GTH
      POTENTIAL GTH-PBE-q6
    &END KIND
    &KIND C
      BASIS_SET aug-TZV2P-GTH
      POTENTIAL GTH-PBE-q4
    &END KIND
    &KIND H
      BASIS_SET aug-TZV2P-GTH
      POTENTIAL GTH-PBE-q1
    &END KIND
  &END SUBSYS
&END FORCE_EVAL