From owner-chemistry |-at-| ccl.net Tue Sep  5 12:22:00 2006
From: "Arvydas Tamulis tamulis+*+mserv.itpa.lt" <owner-chemistry%%server.ccl.net>
To: CCL
Subject: CCL: What it is the correlation between different ionization potentials
Message-Id: <-32482-060905121344-5999-tcVvgveEkyQWMrPBBYS+vQ%%server.ccl.net>
X-Original-From: Arvydas Tamulis <tamulis,,mserv.itpa.lt>
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Date: Tue, 5 Sep 2006 19:13:39 +0300 (EEST)
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Sent to CCL by: Arvydas Tamulis [tamulis_+_mserv.itpa.lt]
Dear Colleagues,

Usually we obtain quantum mechanically (QM) the ionization potentials 
which corresponds well with the experimental data of ionization potential 
of He(I) UV photoelectron (PE) measurements. 
For example, my last year obtained ionization potential using
Koopmans' theorem approximation for guanine is equal to -4.82 eV
(calculations were performed with PBEPBE/6-31+G(2p,2d) method).

I see that biologists (see example: K. Sugden, B. Martin, Environ 
Health Perspect. 2002 October; 110(Suppl 5): 725728.) are 
using data of oxidation potential versus to the normal hydrogen electrode. 
In this article reference [19] the ionization potential for guanine 
is equal to -1.29 V.

My question is what it is the correlation between values of these two
experimental measurements: He(I) UV photoelectron (PE) and oxidation
potential versus to the normal hydrogen electrode? How to transform our
obtained QM results to the experimentally observed oxidation potential
versus to the normal hydrogen electrode?

With best regards,
Arvydas Tamulis