Nuclephile Substitution CH3Cl - mMD3

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Task

In this example the nucleophile substitution of a Cl- by another Cl- in CH3Cl via meta dynamics is simulated using two collective variables simultaneously.

Input

POSCAR

   1.00000000000000
     9.0000000000000000    0.0000000000000000    0.0000000000000000
     0.0000000000000000    9.0000000000000000    0.0000000000000000
     0.0000000000000000    0.0000000000000000    9.0000000000000000
   C    H    Cl
   1   3   2
Direct
  0.1570348572197245  0.2904054711139102  0.1422643997559632
  0.1466469234176954  0.4066467848992589  0.1077433527138946
  0.0469134772399311  0.2399491465236156  0.1544210764126938
  0.2197893311177821  0.2820094213788985  0.2462070949679763
  0.9809163623144840  0.4723904404063168  0.3674924467383788
  0.2601754409903839  0.1874592103557934  0.9964911656110944

KPOINTS

Automatic
 0
Gamma
 1  1  1
 0. 0. 0.
  • For isolated atoms and molecules interactions between periodic images are negligible (in sufficiently large cells) hence no Brillouin zone sampling is necessary.

INCAR

PREC=Low
EDIFF=1e-6
LWAVE=.FALSE.
LCHARG=.FALSE.
NELECT=22
NELMIN=4
LREAL=.FALSE.
ALGO=VeryFast
ISMEAR=-1
SIGMA=0.0516

############################# MD setting #####################################
IBRION=0                                           # MD simulation
NSW=1000                                           # number of steps
POTIM=1                                            # integration step
TEBEG=600                                          # simulation temperature
MDALGO=11                                          # metaDynamics with Andersen thermostat
ANDERSEN_PROB=0.10                                 # collision probability
HILLS_BIN=50                                       # update the time-dependent bias
                                                             # potential every 50 steps
HILLS_H=0.005                                      # height of the Gaussian
HILLS_W=0.05                                       # width of the Gaussian
##############################################################################

ICONST

R 1 5 5
R 1 6 5
  • In contrast to the previous examples two collective variables are used simultaneously (and no combination of them).

Calculation

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