CCL: DFT and dispersion

[Arne Dieckmann <adieckma . googlemail.com>]

 Sent to CCL by: Arne Dieckmann [adieckma]=[googlemail.com]
 Thanks, this is a good point. I will examine if the geometries of my structures
 are significantly affected by including long-range dispersion in the
 optimization.
 Best,
 Arne
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 Dr. Arne Dieckmann
 Houk Research Lab
 University of California, Los Angeles
 email: adieckma^googlemail.com
 On Oct 30, 2011, at 8:49 AM, Stefan Grimme grimme__thch.uni-bonn.de wrote:
 >
 > 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:+:thch.uni-bonn.de)>
 >