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