Subject: KM decomposition

From: Fabrice Leclerc <[email-masked]>
Date: Sun, 29 Dec 2002 22:09:28 +0100

Hi,
I'm working on a supermolecule containing 11 non-covalently bonded 
monomers on which I have performed some energy decomposition analyses 
with the GAMESS package. I'd like to know if any of you could share his 
experience for such analyses with systems involving many-body 
interactions (more than 2 or 3 monomers).

The current implementation of the Kitaura-Morokuma decomposition 
analysis (GAMESS, august 2002) is from  W. Chen & M.S. Gordon (J. Phys. 
Chem., 100, 1996, 14316-14328, "Energy decomposition analysis for 
many-body interactions and applications to water complexes"). A 
standard KM decomposition calculation (RUNTYP=MOROKUMA) gives the usual 
energy components: ES (electrostatic), EX (exchange-repulsion), PL 
(polarization), CT (charge transfer), and MIX (coupling energy). In the 
particular case where there are only 2 monomers, the energy components 
are physically meaningful. In the cases where there are 3 monomers or 
more, the energy components correspond to the contribution from each 
monomer to the ES, EX, PL, CT and MIX terms. In the work by Chen & 
Gordon, they developed a method for many-fragment KM analysis where the 
energy terms for such n-body systems are further partitioned into 
pairwise two-body terms. However, a standard KM decomposition 
calculation does not provide automatically the pairwise two-body terms. 
Does anybody know how to get the pairwise two-body terms ?