From owner-chemistry \\at// ccl.net Wed Jun 10 06:13:00 2015 From: "Sebastian Kozuch seb.kozuch||gmail.com" To: CCL Subject: CCL: Proper way of doing a Boltzmann average Message-Id: <-51438-150610061126-19075-qGxR1eIxXknqcjiYFGtwRA%server.ccl.net> X-Original-From: Sebastian Kozuch Content-Transfer-Encoding: 7bit Content-Type: text/html; charset=windows-1252 Date: Wed, 10 Jun 2015 13:10:37 +0300 MIME-Version: 1.0 Sent to CCL by: Sebastian Kozuch [seb.kozuch|gmail.com] Dear Gustavo,
The matter you are pointing to is not obvious. The partition function may depend on the symmetry number and the indistinguishability of the two systems, factors that can change the Boltzmann distribution. I hope someone with real knowledge can help you, but maybe you can obtain some guidance from the work on reaction rates of Fernandez-Ramos et al. (http://link.springer.com/article/10.1007/s00214-007-0328-0).

Best,
Sebastian

On 10/06/2015 03:37, Gustavo L.C. Moura gustavo.moura|a|ufpe.br wrote:
Sent to CCL by: "Gustavo L.C. Moura" [gustavo.moura%x%ufpe.br]
Dear CCL community,
I am seeking advice about the proper way of calculating a Boltzmann average.
For the sake of argument, let us say that I have a molecule that may assume only two distinct conformations A and B. I have no problems calculating the Boltzmann averaged property in this case.
However, I have strong theoretical and experimental evidences that my molecule forms a hydrogen bonded dimer. The dimerization process does not affect the flexibility of each monomer and they still have the same two conformations A and B as before. I have no problems dealing with the averaging process for the dimers in conformations AA and BB (they are unique). My problem is with conformations AB and BA. The two dimers can be superimposed (and are technically equal), but I still know which monomer has each conformation.
My question is: should I include both dimers in the Boltzmann average or should I include only one of them in the Boltzmann average?
Your advice is most welcome.
Thank you very much in advance.
Sincerely yours,
			Gustavo L.C. MouraE-mail to subscribers: CHEMISTRY-$-ccl.net or use:
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