Example: ReaxFF: ADF geometry optimization using ReaxFF forces¶

#! /bin/sh

# == Expert Option ==

# An example of ADF optimization using ReaxFF forces.

cp "$ADFHOME/atomicdata/ForceFields/ReaxFF/CuCl-H2O.ff" ffield

cat > control <<eor
# General parameters
      0 itrans
      1 icentr     0: off, 1: put center of masss at center of cube, 2: put com at origin
      0 imetho     Normal MD-run 1: Energy minimisation
      5 igeofo     5: read from adf-provided file, calc forces and stop
      0 timing     0: no tining, 2: timing details
  250.0 axis1      a cell axis
  250.0 axis2      b cell axis
  250.0 axis3      c cell axis
 90.000 angle1     cell angles
 90.000 angle2     cell angles
 90.000 angle3     cell angles
     25 irecon     Frequency of reading control-file
      5 ixmolo     xmolout 0: xyz only, 1: xyz + vels + molnr, 2: xyz + mol.nr, 5: xyz + bonds
      1 ichupd     Charge update frequency
      4 icharg     always 4: Full system EEM
 298.00 mdtemp     MD-temperature (K), unless tregime file is present
  100.0 tdamp1     1st Berendsen/Anderson temperature damping constant (fs)
# MD-parameters
      1 imdmet     MD-method. 1:Velocity Verlet+Berendsen 2:Hoover-Nose (again NVT); 3:NVE 4:NPT
  0.250 tstep      MD-time step (fs)
   0.00 mdpres     MD-pressure (GPa)
  500.0 pdamp1     Berendsen pressure damping constant (fs)
      0 inpt       0: Change all cell parameters in NPT-run  1: fixed x 2: fixed y 3: fixed z
      1 nmdit      Number of MD-iterations
      5 iout1      Output frequency to unit 71 and unit 73
   5000 iout2      Save coordinates (xmolout, moldyn.vel, Molfra)
      1 iout3     Create moldyn.xxx files (0: yes, 1: no)
      0 ivels      0: Use velocities from vels restart-file; 1: Zero initial velocities
   2000 iout6      Frequency of molsav.xxxx restart file creation (xyz, vels and accel)
     50 iout7      Frequency of reaxout.kf writing
     25 irten      Frequency of removal of rotational and translational motions
      0 npreit     Nr. of iterations in previous runs
   0.00 range      range for back-translation of atoms outside periodic box
# MM-parameters
1.00000 endmm      End point criterium for MM energy minimisation (force)
      0 imaxmo     0: conjugate gradient, -1: temperature dependent MD minimization (with imethod 1)
      1 imaxit     Maximum number of iterations
      1 iout4      Frequency of structure output during minimisation
      0 icelop     0 : no cell opt, 1: numerical cell opt
1.00010 celopt     Cell parameter change factor
      0 icelo2     0: Cubic cell optimization; 1/2/3: only a/b/c; 4: c/a ratio
eor


NSCM=1
export NSCM

"$ADFBIN/adf" <<eor
ATOMS
O                   9.21547  18.20279   5.17255
H                   9.82360  18.92182   4.93781
H                   9.54331  17.44166   4.66744
O                   4.62358  16.65456  21.14691
H                   3.99888  17.39042  21.24792
H                   5.47889  17.03353  21.40531
O                  21.12941   6.02920   5.89396
H                  21.47696   6.74566   6.44878
H                  20.69255   5.43353   6.52347
END

XC
LDA SCF VWN
END

GEOMETRY
    branch New
    optim cartesian
    iterations 1000
    ExternProgram "sh $ADFBIN/reax2adf"  
    ExternProgram coord=adf_reaxff.coords energy=adf_reaxff.energy grad=adf_reaxff.grad
END

SAVE  TAPE21 TAPE13

NOPRINT LOGFILE

Basis
End
eor