title: Chemical potential and reaction electronic flux in symmetry controlled reactions.
abstract: In symmetry controlled reactions, orbital degeneracies among orbitals of different symmetries can occur along a reaction coordinate. In such case Koopmans' theorem and the finite difference approximation provide a chemical potential profile with nondifferentiable points. This results in an ill-defined reaction electronic flux (REF) profile, since it is defined as the derivative of the chemical potential with respect to the reaction coordinate. To overcome this deficiency, we propose a new way for the calculation of the chemical potential based on a many orbital approach, suitable for reactions in which symmetry is preserved. This new approach gives rise to a new descriptor: symmetry adapted chemical potential (SA-CP), which is the chemical potential corresponding to a given irreducible representation of a symmetry group. A corresponding symmetry adapted reaction electronic flux (SA-REF) is also obtained. Using this approach smooth chemical potential profiles and well defined REFs are achieved. An application of SA-CP and SA-REF is presented by studying the Cs enol-keto tautomerization of thioformic acid. Two SA-REFs are obtained, JA'(ξ) and JA'' (ξ). It is found that the tautomerization proceeds via an in-plane delocalized 3-center 4-electron O-H-S hypervalent bond which is predicted to exist only in the transition state (TS) region. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Departamento De Físico-Qímica, Facultad De Ciencias Químicas, Universidad De Concepción, Casilla 160-C, Concepción, Chile.|Nucleus Millennium Chemical Processes and Catalysis, Laboratorio De Química Teórica Computacional (QTC), Departamento De Química-Física, Facultad De Química, Pontificia Universidad Católica De Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, 9900087, Chile.
authors.forename: Stefan
authors.initials: S
authors.lastname: Vogt-Geisse
authors.affiliation: Nucleus Millennium Chemical Processes and Catalysis, Laboratorio De Química Teórica Computacional (QTC), Departamento De Química-Física, Facultad De Química, Pontificia Universidad Católica De Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, 9900087, Chile.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Toro-Labbé
keywords: conceptual DFT; denisty functional theory; electronic chemical potential; reaction electronic flux; symmetry