title: Vibrational control of electron-transfer reactions: a feasibility study for the fast coherent transfer regime.
abstract: Molecular vibrations and electron-vibrational interactions are central to the control of biomolecular electron and energy-transfer rates. The vibrational control of molecular electron-transfer reactions by infrared pulses may enable the precise probing of electronic-vibrational interactions and of their roles in determining electron-transfer mechanisms. This type of electron-transfer rate control is advantageous because it does not alter the electronic state of the molecular electron-transfer system or irreversibly change its molecular structure. For bridge-mediated electron-transfer reactions, infrared (vibrational) excitation of the bridge linking the electron donor to the electron acceptor was suggested as being capable of influencing the electron-transfer rate by modulating the bridge-mediated donor-to-acceptor electronic coupling. This kind of electron-transfer experiment has been realized, demonstrating that bridge-mediated electron-transfer rates can be changed by exciting vibrational modes of the bridge. Here, we use simple models and ab initio computations to explore the physical constraints on one's ability to vibrationally perturb electron-transfer rates using infrared excitation. These constraints stem from the nature of molecular vibrational spectra, the strengths of the electron-vibrational coupling, and the interaction between molecular vibrations and infrared radiation. With these constraints in mind, we suggest parameter regimes and molecular architectures that may enhance the vibrational control of electron transfer for fast coherent electron-transfer reactions.
authors.affiliation: Department of Physics, University of Cyprus, Nicosia 1678, Cyprus. skourtis@ucy.ac.cy.
authors.forename: P
authors.initials: P
authors.lastname: Antoniou
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina, 27708 USA. david.beratan@duke.edu.
authors.forename: Z
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina, 27708 USA. david.beratan@duke.edu.
authors.forename: P
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina, 27708 USA. david.beratan@duke.edu and Department of Physics, Duke University, Durham, North Carolina, 27708 USA.
authors.forename: D N
authors.initials: DN
authors.lastname: Beratan
authors.affiliation: Department of Physics, University of Cyprus, Nicosia 1678, Cyprus. skourtis@ucy.ac.cy and Freiburg institute of Advanced Studies (FRIAS), University of Freiburg, 79104 Freiburg, Germany.
authors.forename: S S
authors.initials: SS
authors.lastname: Skourtis
mesh_terms: D004579:Electron Transport; D004583:Electrons; D007259:Infrared Rays; D008665:Metalloporphyrins / Q000737:chemistry; D008962:Models, Theoretical; D011789:Quantum Theory; D014466:Ultraviolet Rays; D014732:Vibration
chemical_list: D008665:Metalloporphyrins; C017802:zinc hematoporphyrin