Formaldehyde: another Optimization

Sample directory: adf/GO_Formaldehyde/

In the input for the optimization run the atomic coordinates are in Z-matrix format while the optimization variables are the Cartesian coordinates. This is achieved with the optim subkey in the geometry block.

A single geovar variable is used for different coordinates. However, since the type of optimization variables (Cartesian) is not the same as the type of input coordinates (Z-matrix), no constraints are implied by this. In fact, the related coordinates do remain equal, but this is because they are symmetry related and the program preserves symmetry anyway.

NonLocal gradient corrections (gga: Generalized Gradient Approximation) according to the approach known as 'Becke' (for exchange) and 'Perdew' (correlation) are included self-consistently with the key xc.

$ADFBIN/adf << eor
Title  formaldehyde

Geometry
 Optim  cartes
End

XC
  GGA Becke Perdew
END

Symmetry  C(2v)

Atoms  Z-matrix
  1 O   0 0 0  0.0  0.0  0.0
  2 C   1 0 0  r2   0.0  0.0
  3 H   2 1 0  r3   a3   0.0
  4 H   2 1 3  r3   a3   t4 
End

Fragments
  C  t21.C
  O  t21.O
  H  t21.H
End

Geovar
 r2     1.94
 r3     0.95
 a3   120
 t4  -180
End

integration 4.5

End Input
eor