Editing G09 (section)

== 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-electrostatic terms.