title: Topological analyses of time-dependent electronic structures: application to electron-transfers in methionine enkephalin.
abstract: We have studied electron transfers (ET) between electron donors and acceptors, taking as illustrative example the case of ET in methionine enkephalin. Recent pulse and gamma radiolysis experiments suggested that an ultrafast ET takes place from the C-terminal tyrosine residue to the N-terminal, oxidized, methionine residue. According to standard theoretical frameworks like the Marcus theory, ET can be decomposed into two successive steps: i) the achievement through thermal fluctuations, of a set of nuclear coordinates associated with degeneracy of the two electronic states, ii) the electron tunneling from the donor molecular orbital to the acceptor molecular orbital. Here, we focus on the analysis of the time-dependent electronic dynamics during the tunneling event. This is done by extending the approaches based on the topological analyses of stationary electronic density and of the electron localization function (ELF) to the time-dependent domain. Furthermore, we analyzed isosurfaces of the divergence of the current density, showing the paths that are followed by the tunneling electron from the donor to the acceptor. We show how these functions can be calculated with constrained density functional theory. Beyond this work, the topological tools used here can open up new opportunities for the electronic description in the time-dependent domain.
authors: Laboratoire de Chimie Théorique, UPMC Université Paris 06, UMR 7616, F-75005, Paris, France, julien.pilme@lct.jussieu.fr.
authors: Julien
authors: J
authors: Pilmé
authors: Eleonora
authors: E
authors: Luppi
authors: Jacqueline
authors: J
authors: Bergès
authors: Chantal
authors: C
authors: Houée-Lévin
authors: Aurélien
authors: A
authors: de la Lande
mesh_terms: D004583:Electrons; D004744:Enkephalin, Methionine / Q000737:chemistry*; D008958:Models, Molecular; D013997:Time Factors
chemical_list: D004744:Enkephalin, Methionine