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W Schmickler

Publications and source records attributed to W Schmickler.

5 recordsLinked to original sources
PubMed2004

Potential energy surface for an electron transfer reaction mediated by a metal adlayer.

A model Hamiltonian for electron transfer from a metal electrode to a solvated reactant via a metallic adsorbate is proposed. The adsorbates are distributed randomly over the electrode surface, and a coherent-potential approximation has been employed to treat this randomness. Both the adsorbates and the reactant are assumed to interact with the solvent, which is modeled as a bath of phonons with frequencies in the classical regime. Both the adiabatic and the nonadiabatic potential energy surfaces are calculated, and their dependence on the adsorbate coverage is highlighted. In the low coverage regime the potential-energy surfaces exhibit features similar to a bridge-assisted electron transfer reaction, whereas for higher coverages the surfaces resemble those for direct heterogeneous transfer. This change of shape is caused by the metallization of the adsorbate layer at higher coverages.

Journal Article↗
PubMed2004

Electron exchange between two electrodes mediated by two electroactive adsorbates.

Experimental data for electron exchange between two electrodes covered by electroactive films are presented and discussed in terms of the Gerischer model. A model Hamiltonian is proposed for such indirect electron exchange involving two intermediate species. Explicit model calculations are performed for the case in which the coupling between the two adsorbates is weak and determines the overall rate. The calculations agree well with the experimental data, and can be used to determine the energy of reorganization associated with the electron transfer.

Journal Article↗
PubMed2003

Step line tension on a metal electrode.

The step line tension in electrochemical systems differs conceptually from the line tension on metals in the vacuum because it refers to different boundary conditions. A procedure is established for calculating the electrochemical line tension and is applied to a novel model of the interface comprising both a stepped metal electrode and an electrolyte solution. To first order, the potential dependence of the line tension is governed by the energy of the step dipole in the electric field of the space charge in the solution.

Journal Article↗
PubMed2000

Exactly solvable quantum model for electrochemical electron-transfer reactions.

We consider electron exchange between a metal electrode and a solvated reactant coupled to a harmonic oscillator bath. In the wide-band approximation the time development of the occupation probability for the reactant orbital can be calculated explicitly. From the behavior at long times we derive an expression for the reaction rate that is valid for all strengths of the electronic interaction between the metal and the reactant. The rate constant is related to the scattering matrix for electron exchange between a metal substrate and a scanning tunneling microscope via an electroactive adsorbate.

Journal Article↗