ORCA

UV Visible Spectra of lanthanide complexes can be calculated from Sparkle Model optimized geometries, followed by ORCA calculations, in which the lanthanide ion is replaced by a +3point charge.

The required citation, where this procedure has been first described, is:

Gabedit

Using GABEDIT to visualize MOPAC lanthanide complexes output files:

  1. Insert the keyword AUX in your MOPAC2012 .mop file.
     
  2. Run your MOPAC2012 calculation. An .aux file will be also produced, along with the .out and .arc files.

Global Geometry Minimum

The concept of a global minimum is easy to grasp. Please, consider the function below:

Graph Local Global

This function has five different minima: A, B, G, C, and D.

Four of them, A, B, C, and D, are called local minima because they are minima within a certain region around them.

True Geometry Minimum

The problem

After optimizing the geometry of a molecular system or lanthanide complex and verifying that the norm of the gradient has been sufficiently reduced, users tend to be satisfied with the geometry obtained and proceed to compute other properties.

Is this warranted?

No!

Actually it is very important to determine if this geometry corresponds to a true minimum in the potential energy hypersurface where the atoms move.

How?

The solution