G09

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Solvent Effects

As with Gaussian03, the SCRF keyword requests that a calculation be performed in the presence of a solvent by placing the solute in a cavity within the solvent reaction field.

• The integral equation formalism variant IEFPCM, is the default SCRF method. It has not changed from Gaussian03, BUT the formalism used and its implementation has changed. That is: you will get different results in G03 and G09, using the same method.

• The default RADII used in G03 was UAO , whilst now is UFF with spheres placed by default on all Hydrogen atoms. No need to use the SPHEREONH= keyword, except if you use UAO or another radii model that does not have them explicitly.

• It seems to give no "convergence failure" problems, but maybe its too early to say so.

• It is able to perform frequency calculations in solvent, giving enthalpies, free energies, ZPE corrections...

• The G09 output for PCM gives only one energy which corresponds, by default, to the electrostic energy. The non-electroestatic components of the energy of solvation are not included. If you wish to include them you will need to include "scrf=(read,PCM,...)" in the command line, and Cav Dis Rep (in separate lines) at the end of the input.

• The SMD method includes automatically the non-electroestatic terms.

Gaussian09 vs Gaussian03

• Scaling and New Functional Testing

• Solvation models, Polarizable Continuum Model (PCM)

• Tests on solvation energies, PCM in G03 and G09 and SMD