From owner-chemistry@ccl.net Sun Oct 30 13:09:00 2011
From: "Stefan Grimme grimme__thch.uni-bonn.de" <owner-chemistry=-=server.ccl.net>
To: CCL
Subject: CCL: DFT and dispersion
Message-Id: <-45779-111030114953-26710-gXpq46e1wsQrCYs7SxiM9Q=-=server.ccl.net>
X-Original-From: "Stefan  Grimme" <grimme]~[thch.uni-bonn.de>
Date: Sun, 30 Oct 2011 11:49:51 -0400


Sent to CCL by: "Stefan  Grimme" [grimme\a/thch.uni-bonn.de]
>First, I would like to thank all of you for your comments and help. I >strongly believe in the principle of getting the right answers for the right >reasons, which is why I want to make sure I am using methods in the context >they were developed for. With regards to solution corrections: As the DFT-D3 >model is only geometry-dependent, I guess the following procedure would be >valid: 
>1. Optimize the geometry in the gas phase 
>2. Calculate energy in solution (e.g. using SMD) 
>3. Add DFT-D3 dispersion correction 
>4. Add thermal corrections 
>Would you agree? 
Basically yes but I would also use the dispersion correction for the geometry
optimization as well. Structures of 'normal' molecules are less affected by dispersion than energies but conformations are sometimes sensitive to details in the potential.
Cheers!
Stefan Grimme (grimme a thch.uni-bonn.de)