H₂O: new constraint Geometry Optimization

Sample directory: adf/GO_newconstraints/

The key NEWCONSTRAINTS can only be used in case of the New branch for optimization of coordinates. The input for this key is very similar to that of the RESTRAINT keyword. The key NEWCONSTRAINTS can, however, also be used to constrain Cartesian coordinates. Note that the key RESTRAINT and freezing of coordinates with the GEOVAR key can also be used in the New branch for optimization of coordinates. In ADF2007 the New branch for optimization can only be used in geometry optimizations and transition state searches.

The constraints do not have to be satisfied at the start of the geometry optimization.

Example for angle restraint

$ADFBIN/adf << eor
title WATER geometry optimization with angle constraint

ATOMS
    1.O         0.001356    0.000999    0.000000
    2.H         0.994442   -0.037855    0.000000
    3.H        -0.298554    0.948531    0.000000
END

BASIS
 Type DZP
END

INTEGRATION 4 4

NEWCONSTRAINTS
  ANGLE  3 1 2 125.0
END

GEOMETRY
  OPTIM DELOCAL
END

endinput
eor

Example for fixed-atom constraint. Note that the optimization should be done in Cartesian.

$ADFBIN/adf << eor
title WATER geometry optimization with fixed-atom constraint

ATOMS
    1.O         0.001356    0.000999    0.000000
    2.H         0.994442   -0.037855    0.000000
    3.H        -0.298554    0.948531    0.000000
END

BASIS
 Type DZP
END

INTEGRATION 4 4

SYMMETRY NOSYM

NEWCONSTRAINTS
  ATOM 1 0.0 0.0 0.0
  ATOM 2 1.0 0.0 0.0
END

GEOMETRY
  OPTIM CARTESIAN
  BRANCH NEW
END

endinput
eor

Example for bond length restraint.

$ADFBIN/adf << eor
title WATER Geometry Optimization with bond length constraint

ATOMS
    1.O         0.001356    0.000999    0.000000
    2.H         0.994442   -0.037855    0.000000
    3.H        -0.298554    0.948531    0.000000
END

BASIS
 Type DZP
END

INTEGRATION 4 4

NEWCONSTRAINTS
  DIST  1 2 1.03
  DIST  1 3 1.03
END

GEOMETRY
  OPTIM CARTESIAN
  BRANCH NEW
END

endinput
eor

Example for dihedral angle restraint

$ADFBIN/adf << eor
Title Constraining dihedral of ethane

SYMMETRY NOSYM

ATOMS
  1.C        -0.004115   -0.000021    0.000023
  2.C         1.535711    0.000022    0.000008
  3.H        -0.399693    1.027812   -0.000082
  4.H        -0.399745   -0.513934    0.890139
  5.H        -0.399612   -0.513952   -0.890156
  6.H         1.931188    0.514066    0.890140
  7.H         1.931432    0.513819   -0.890121
  8.H         1.931281   -1.027824    0.000244
END

INTEGRATION 4 4

RESTRAINT
  DIHED   6    2    1    3     20.00
END

BASIS
  type DZP
END

GEOMETRY
  OPTIM DELOCAL
END

endinput
eor