#! /bin/sh

# The restraint does not have to be satisfied at the start of the geometry
# optimization. An extra force is added to restrain the bond length, angle, or
# dihedral angle to a certain value.


#  == angle restraint ==


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

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

RESTRAINT
  ANGLE  3 1 2 125.0
END

GEOMETRY
END

eor

rm TAPE21 logfile


# == bond length restraint ==


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

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

RESTRAINT
  DIST  1 2 1.03
  DIST  1 3 1.03
END

GEOMETRY
END

eor

rm TAPE21 logfile


# == Restraining dihedral ==


$ADFBIN/adf <<eor
Title Restraining 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

RESTRAINT
  DIHED  6 2 1 3  20.00
END

BASIS
  type DZP
END

GEOMETRY
END

eor

mv TAPE21 C2H6.t21