Example: Geometry Optimization: Formaldehyde¶

Download GO_Formaldehyde.run

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
Basis
Type DZP
End
Geovar
r2     1.94
r3     0.95
a3   120
t4  -180
End
BeckeGrid
Quality Good
End
End Input
eor