Subject: Re: CCL:BSSE on Dimers

From: uccatvm <[email-masked]>
Date: Sat, 7 Jul 2001 20:29:29 +0100 (BST)

Hi Demetrio,
  
> I am doing some MP2/6-311G(2d,2p) canculation on
> anthracene dimers (using Gaussian'98) and I want to
> know how I can eliminate the BSSE (basis set
> superposition error) using the counterpoise method
> for that system of two equal molecules.
> 
> I wonder if someone can point me to articles or
> a scheme in order to do that using Gaussian'98.

If you calculate a binding energy De as:
De = E{AB} -E{A} - E{B}
Using counterpoise, you calculate the monomer energies E{A} and E{B} 
also in the complete dimer basis set. In Gaussian, you do this by
setting the nuclear charge of the second dimer (B for E{A} and 
A for E{B}) to zero. This is done by the Massage keyword; see the
examples in the Gaussian manual (www.gaussian.com/00000452.htm).
(but don't believe what the manual says about counterpoise only
providing "a crude estimate" - see papers below).

Depending on how much your monomer geometries change upon complexation,
you may also have to take into account the monomer deformation energies
(the energy it takes to bring an anthracene molecule to the geometry it
has in the complex).

Some references:
-  F.B. van Duijneveldt, J.G.C.M. van Duijneveldt-van de Rijdt, and
   J.H. van Lenthe, Chem. Rev. 94, 1873, 1994 (on counterpoise theory)

-  S. Simon, M. Duran, J.J. Dannenberg, J. Chem. Phys. 105, 1996
   (on geometry optimizations on BSSE-corrected potential energy surfaces).

-  F.B. van Duijneveldt, "Basis Superposition Error"
   in "Molecular Interactions" S. Scheiner (ed.), Wiley (1997)

-  T. van Mourik, A.K. Wilson, K.A. Peterson, D.E. Woon, T.H. Dunning, Jr.,
   Adv. Quant. Chem. 31, 105, 1999 (showing BSSE effects on interaction
   energies, distances, and frequencies).

You may also want to search the ccl archives; there have been a few disussions
on counterpoise the last few years.

Hope that helps,

Tanja
-- 
  =====================================================================
     Tanja van Mourik                                                
     Royal Society University Research Fellow
     Chemistry Department 
     University College London    phone:    +44 (0)20-7679-4663      
     20 Gordon Street             e-mail:   work: [email-masked] 
     London WC1H 0AJ, UK                    home: [email-masked]     

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