Wolfgang Schmickler - Academia.edu (original) (raw)

Papers by Wolfgang Schmickler

Research paper thumbnail of Rundum nützlich: Elektrochemisches Praktikum. Von Rudolf Holze. B. G. Teubner, Stuttgart 2001. 302 Seiten, brosch. 32,72 Euro. ISBN 3-519-03614-2

Nachrichten Aus Der Chemie, Feb 1, 2002

Research paper thumbnail of Elektrochemie: Instrumental Methods in Electrochemistry. Southampton Electrochemistry Group. R. Greef, R. Peat, L. M. Peter, D. Pletcher und J. Robinson. Halsted Press 1985. 443 S., Tab., £ 49,50. ISBN 0 853128758

Nachrichten aus Chemie, Technik und Laboratorium, Jul 1, 1986

Research paper thumbnail of Tip effects in the scanning-tunneling microscopy of semiconductor electrodes

Surface Science, May 1, 2001

The surface properties of a WSe 2 electrode have been investigated with a scanning-tunneling micr... more The surface properties of a WSe 2 electrode have been investigated with a scanning-tunneling microscope in an electrochemical cell. Current±potential curves have been obtained for various electrode potentials and tunneling distances. They show a strong in¯uence of the tip on the local electrode potential. The main features can be understood within a simple model describing the distribution of the electrostatic potential and its eect on the local electronic density.

Research paper thumbnail of On the Theory of Electrocatalysis

Springer eBooks, 2017

A theory of electrocatalysis developed in our group is presented and related to other theories of... more A theory of electrocatalysis developed in our group is presented and related to other theories of electrochemical electron transfer. As an example, the theory is applied to the first step in oxygen reduction on silver in alkaline media. It is shown, that this step occurs in the outer sphere mode.

Research paper thumbnail of Electron exchange between two electrodes mediated by two electroactive adsorbates

Faraday Discussions, 2004

Experimental data for electron exchange between two electrodes covered by electroactive films are... more 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.

Research paper thumbnail of Kein Meisterstück der Elektrochemie: Electrochemistry - Principles, Methods, and Applications. Von C. M. A. Brett und A. M. Olivera Brett. Oxford University Press, Oxford, 1993. 427 S., Abb., Tab., kart. 25,- £. ISBN 0-19-855388-9

Nachrichten aus Chemie, Technik und Laboratorium, Jun 1, 1994

Research paper thumbnail of Elektrochemische Kinetik. Von W. Forker. Akademie Verlag, Berlin 1989. 254 S., Broschur DM 38.00. — ISBN 3-05-500486-8

Angewandte Chemie, Jul 1, 1990

und der Leser ist beispielsweise gut beraten, Informationen zur asymmetrischen Synthese nicht nur... more und der Leser ist beispielsweise gut beraten, Informationen zur asymmetrischen Synthese nicht nur in Kapitel21 zu suchen. Wichtige Oxygenierungen sind nicht nur in Kapitell7, sondern ebenso unter Reaktionen mit Elektrophilen (Kapitel 12) zu finden.

Research paper thumbnail of Ein Dipolmodell für die äußere Solvatationssphäre und seine Anwendung auf Elektronen-Übergangs-Reaktionen der äußeren Sphäre

Colloid and Polymer Science, Mar 1, 1978

Research paper thumbnail of J. O'M. Bockris, Shahed U.M. Khan: Surface electrochemistry, a molecular level approach. Plenum Press, New York, London, 1993. ISBN 0-306-44298-1, 1014 Seiten, Preis: $79.50

Berichte der Bunsengesellschaft für physikalische Chemie, Sep 1, 1994

Research paper thumbnail of P. Vanysek: Electrochemistry on Liquid/Liquid Interfaces. Vol. 39 aus der Reihe: Lecture Notes in Chemistry, Springer-Verlag, Berlin, Heidelberg, New York, Tokyo 1985. 106 Seiten, Preis: DM 30

Berichte der Bunsengesellschaft für physikalische Chemie, Oct 1, 1986

Research paper thumbnail of Geschichte Der Elektrochemie. Von L. Dunsch. VEB Deutscher Verlag für Grundstoffindustrie, Leipzig 1985. 154 S., Broschur, DM 14.00. – Bestell-Nr. 5418814

Research paper thumbnail of A computer simulation of two-dimensional growth

Journal of electroanalytical chemistry and interfacial electrochemistry, Dec 1, 1986

Abstract A model for the growth of a two-dimensional cluster on a surface is investigated which a... more Abstract A model for the growth of a two-dimensional cluster on a surface is investigated which accounts both for surface diffusion and for direct incorporation from an adjoining bulk phase. The computer simultations produce irregularly shaped structures with dendrite-like features at their edges, which can be described in terms of fractal geometry. For the range of system parameters investigated, the growth obeys relatively simple time laws as long as the cluster is small compared to the size of the finite lattice employed in the simulation.

Research paper thumbnail of Ion association at liquid|liquid interfaces

Journal of Electroanalytical Chemistry, Oct 1, 1997

Ion association at the interface between two immiscible electrolyte solutions may manilest itself... more Ion association at the interface between two immiscible electrolyte solutions may manilest itself as a marked increase in the intert~lcial capacity. This effect is illustrated by experimental Investigations in which the ions in the organic phase are varied, while the composition of the aqueous phase is kept constant. The increase in the capacity is explained by a simple lattice-gas model. The mag~aitude of this effect depends both on the association constant and the width of the interfi~ce, fO 1997 Elsevier Science S.A.

Research paper thumbnail of The investigation of redox reactions with a scanning tunneling microscope

Journal of Electroanalytical Chemistry, Sep 1, 1992

Abstract The tunneling current between the tip and a sample in a scanning tunneling microscope (S... more Abstract The tunneling current between the tip and a sample in a scanning tunneling microscope (STM) can be enhanced by the presence of an electroactive adsorbate on the sample. We have used the transfer Hamiltonian mechanism to determine the dependence of this current on various system parameters like the bias voltage, the energy of reorganization, and electronic coupling of the redox centre to the tip and the substrate. We estimate that a fast redox couple would rise give to currents in the pA to nA range; furthermore, the adsorbate density of states will be reflected in d j /d V . We also discuss experimental considerations in examining electron transfer via a redox adsorbate using an STM.

Research paper thumbnail of Model for the growth of a two-dimensional cluster

The Journal of Physical Chemistry, Apr 1, 1989

... Brigitte Marner and Wolfgang Schmickler* Institute of Physical Chemistry, University of Bonn,... more ... Brigitte Marner and Wolfgang Schmickler* Institute of Physical Chemistry, University of Bonn, Wegelerstrasse 12, 0-5300 Bonn, FRG (Received: November 30, 1987; In Final Form: March 30, 1988) ... The solid lins reprsent the results of fits with the function f according to eq I. ...

Research paper thumbnail of A diffusion model for the latency of an electroretinogram

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1981

The diffusion model of Cone for the latency of the b-wave in the electroretinogram is discussed. ... more The diffusion model of Cone for the latency of the b-wave in the electroretinogram is discussed. It is shown that Cone's original equation is valid only if the time of illumination is short compared to the latency. A general relation between the intensity of illumination and the latency is derived which holds for arbitrary illumination times. This theoretical result is compared with recent experimental data for the electroretinogram of the frog. By fitting two parameters, good agreement between theory and experiment is achieved. From these parameters an estimate is obtained for the diffusion length of the transmitter substance.

Research paper thumbnail of Interfacial Electrochemistry

Electrochemistry is the study of a special class of interfaces--those between an ionic and an ele... more Electrochemistry is the study of a special class of interfaces--those between an ionic and an electronic conductor--that can conduct current. This makes it especially important to research and for industrial applications such as semiconductors. This book examines different topics within interfacial electrochemistry, including the theory of structures and processes at metal- solution and semiconductor-solution interfaces, the principles of classical and modern experimental methods, and some of the applications of electrochemistry. Students and nonspecialists in materials science, surface science, and chemistry will find this a valuable source of information.

Research paper thumbnail of A simple model for the growth of two-dimensional metal clusters

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1990

Recently we have investigated the growth of a two-dimensional cluster, which grows both through s... more Recently we have investigated the growth of a two-dimensional cluster, which grows both through surface diffusion and direct incorporation from a solution, by Monte Carlo techniques. In this communication, we would like to demonstrate that a simple modification of our simulation rules results in a model which is better suited to describe the growth of two-dimensional metal clusters

Research paper thumbnail of A monte carlo study of point dipole models for solvent molecules in the inner layer

Journal of Electroanalytical Chemistry, 1983

Several point dipole models for the inner layer are investigated by Monte Carlo techniques. In th... more Several point dipole models for the inner layer are investigated by Monte Carlo techniques. In the absence of an external field, an exact point dipole model shows a thermally disturbed structure, in which the dipoles are preferentially oriented in the plane. The dependence of the mean orientation along the field direction as a function of the field strength is obtained. Simpler dipole models tend to give misleading results. * Dedicated to W. Vielstich on the occasion of his 60th birthday.

Research paper thumbnail of Electron Transfer Reactions at Oxide Electrodes Involving Tunnelling through a Space Charge Barrier

Berichte der Bunsengesellschaft für physikalische Chemie, 1978

Electron exchange between the conduction band of an oxide electrode and a redox electrolyte in th... more Electron exchange between the conduction band of an oxide electrode and a redox electrolyte in the presence of a space charge barrier is investigated. Two electron transfer mechanisms through the barrier are studied in detail: direct elastic tunnelling and resonance tunnelling via localized states in the band gap. Current/overpotential characteristics are calculated for both mechanisms in dependence on various system parameters such as the Debye length and the band bending. Though the characteristics have a number of features in common, some criteria can be established to distinguish between the two types of tunnelling. The theoretical results are compared with data from several experimental studies; there is evidence that both tunnelling mechanisms occur in real systems.

Research paper thumbnail of Rundum nützlich: Elektrochemisches Praktikum. Von Rudolf Holze. B. G. Teubner, Stuttgart 2001. 302 Seiten, brosch. 32,72 Euro. ISBN 3-519-03614-2

Nachrichten Aus Der Chemie, Feb 1, 2002

Research paper thumbnail of Elektrochemie: Instrumental Methods in Electrochemistry. Southampton Electrochemistry Group. R. Greef, R. Peat, L. M. Peter, D. Pletcher und J. Robinson. Halsted Press 1985. 443 S., Tab., £ 49,50. ISBN 0 853128758

Nachrichten aus Chemie, Technik und Laboratorium, Jul 1, 1986

Research paper thumbnail of Tip effects in the scanning-tunneling microscopy of semiconductor electrodes

Surface Science, May 1, 2001

The surface properties of a WSe 2 electrode have been investigated with a scanning-tunneling micr... more The surface properties of a WSe 2 electrode have been investigated with a scanning-tunneling microscope in an electrochemical cell. Current±potential curves have been obtained for various electrode potentials and tunneling distances. They show a strong in¯uence of the tip on the local electrode potential. The main features can be understood within a simple model describing the distribution of the electrostatic potential and its eect on the local electronic density.

Research paper thumbnail of On the Theory of Electrocatalysis

Springer eBooks, 2017

A theory of electrocatalysis developed in our group is presented and related to other theories of... more A theory of electrocatalysis developed in our group is presented and related to other theories of electrochemical electron transfer. As an example, the theory is applied to the first step in oxygen reduction on silver in alkaline media. It is shown, that this step occurs in the outer sphere mode.

Research paper thumbnail of Electron exchange between two electrodes mediated by two electroactive adsorbates

Faraday Discussions, 2004

Experimental data for electron exchange between two electrodes covered by electroactive films are... more 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.

Research paper thumbnail of Kein Meisterstück der Elektrochemie: Electrochemistry - Principles, Methods, and Applications. Von C. M. A. Brett und A. M. Olivera Brett. Oxford University Press, Oxford, 1993. 427 S., Abb., Tab., kart. 25,- £. ISBN 0-19-855388-9

Nachrichten aus Chemie, Technik und Laboratorium, Jun 1, 1994

Research paper thumbnail of Elektrochemische Kinetik. Von W. Forker. Akademie Verlag, Berlin 1989. 254 S., Broschur DM 38.00. — ISBN 3-05-500486-8

Angewandte Chemie, Jul 1, 1990

und der Leser ist beispielsweise gut beraten, Informationen zur asymmetrischen Synthese nicht nur... more und der Leser ist beispielsweise gut beraten, Informationen zur asymmetrischen Synthese nicht nur in Kapitel21 zu suchen. Wichtige Oxygenierungen sind nicht nur in Kapitell7, sondern ebenso unter Reaktionen mit Elektrophilen (Kapitel 12) zu finden.

Research paper thumbnail of Ein Dipolmodell für die äußere Solvatationssphäre und seine Anwendung auf Elektronen-Übergangs-Reaktionen der äußeren Sphäre

Colloid and Polymer Science, Mar 1, 1978

Research paper thumbnail of J. O'M. Bockris, Shahed U.M. Khan: Surface electrochemistry, a molecular level approach. Plenum Press, New York, London, 1993. ISBN 0-306-44298-1, 1014 Seiten, Preis: $79.50

Berichte der Bunsengesellschaft für physikalische Chemie, Sep 1, 1994

Research paper thumbnail of P. Vanysek: Electrochemistry on Liquid/Liquid Interfaces. Vol. 39 aus der Reihe: Lecture Notes in Chemistry, Springer-Verlag, Berlin, Heidelberg, New York, Tokyo 1985. 106 Seiten, Preis: DM 30

Berichte der Bunsengesellschaft für physikalische Chemie, Oct 1, 1986

Research paper thumbnail of Geschichte Der Elektrochemie. Von L. Dunsch. VEB Deutscher Verlag für Grundstoffindustrie, Leipzig 1985. 154 S., Broschur, DM 14.00. – Bestell-Nr. 5418814

Research paper thumbnail of A computer simulation of two-dimensional growth

Journal of electroanalytical chemistry and interfacial electrochemistry, Dec 1, 1986

Abstract A model for the growth of a two-dimensional cluster on a surface is investigated which a... more Abstract A model for the growth of a two-dimensional cluster on a surface is investigated which accounts both for surface diffusion and for direct incorporation from an adjoining bulk phase. The computer simultations produce irregularly shaped structures with dendrite-like features at their edges, which can be described in terms of fractal geometry. For the range of system parameters investigated, the growth obeys relatively simple time laws as long as the cluster is small compared to the size of the finite lattice employed in the simulation.

Research paper thumbnail of Ion association at liquid|liquid interfaces

Journal of Electroanalytical Chemistry, Oct 1, 1997

Ion association at the interface between two immiscible electrolyte solutions may manilest itself... more Ion association at the interface between two immiscible electrolyte solutions may manilest itself as a marked increase in the intert~lcial capacity. This effect is illustrated by experimental Investigations in which the ions in the organic phase are varied, while the composition of the aqueous phase is kept constant. The increase in the capacity is explained by a simple lattice-gas model. The mag~aitude of this effect depends both on the association constant and the width of the interfi~ce, fO 1997 Elsevier Science S.A.

Research paper thumbnail of The investigation of redox reactions with a scanning tunneling microscope

Journal of Electroanalytical Chemistry, Sep 1, 1992

Abstract The tunneling current between the tip and a sample in a scanning tunneling microscope (S... more Abstract The tunneling current between the tip and a sample in a scanning tunneling microscope (STM) can be enhanced by the presence of an electroactive adsorbate on the sample. We have used the transfer Hamiltonian mechanism to determine the dependence of this current on various system parameters like the bias voltage, the energy of reorganization, and electronic coupling of the redox centre to the tip and the substrate. We estimate that a fast redox couple would rise give to currents in the pA to nA range; furthermore, the adsorbate density of states will be reflected in d j /d V . We also discuss experimental considerations in examining electron transfer via a redox adsorbate using an STM.

Research paper thumbnail of Model for the growth of a two-dimensional cluster

The Journal of Physical Chemistry, Apr 1, 1989

... Brigitte Marner and Wolfgang Schmickler* Institute of Physical Chemistry, University of Bonn,... more ... Brigitte Marner and Wolfgang Schmickler* Institute of Physical Chemistry, University of Bonn, Wegelerstrasse 12, 0-5300 Bonn, FRG (Received: November 30, 1987; In Final Form: March 30, 1988) ... The solid lins reprsent the results of fits with the function f according to eq I. ...

Research paper thumbnail of A diffusion model for the latency of an electroretinogram

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1981

The diffusion model of Cone for the latency of the b-wave in the electroretinogram is discussed. ... more The diffusion model of Cone for the latency of the b-wave in the electroretinogram is discussed. It is shown that Cone's original equation is valid only if the time of illumination is short compared to the latency. A general relation between the intensity of illumination and the latency is derived which holds for arbitrary illumination times. This theoretical result is compared with recent experimental data for the electroretinogram of the frog. By fitting two parameters, good agreement between theory and experiment is achieved. From these parameters an estimate is obtained for the diffusion length of the transmitter substance.

Research paper thumbnail of Interfacial Electrochemistry

Electrochemistry is the study of a special class of interfaces--those between an ionic and an ele... more Electrochemistry is the study of a special class of interfaces--those between an ionic and an electronic conductor--that can conduct current. This makes it especially important to research and for industrial applications such as semiconductors. This book examines different topics within interfacial electrochemistry, including the theory of structures and processes at metal- solution and semiconductor-solution interfaces, the principles of classical and modern experimental methods, and some of the applications of electrochemistry. Students and nonspecialists in materials science, surface science, and chemistry will find this a valuable source of information.

Research paper thumbnail of A simple model for the growth of two-dimensional metal clusters

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1990

Recently we have investigated the growth of a two-dimensional cluster, which grows both through s... more Recently we have investigated the growth of a two-dimensional cluster, which grows both through surface diffusion and direct incorporation from a solution, by Monte Carlo techniques. In this communication, we would like to demonstrate that a simple modification of our simulation rules results in a model which is better suited to describe the growth of two-dimensional metal clusters

Research paper thumbnail of A monte carlo study of point dipole models for solvent molecules in the inner layer

Journal of Electroanalytical Chemistry, 1983

Several point dipole models for the inner layer are investigated by Monte Carlo techniques. In th... more Several point dipole models for the inner layer are investigated by Monte Carlo techniques. In the absence of an external field, an exact point dipole model shows a thermally disturbed structure, in which the dipoles are preferentially oriented in the plane. The dependence of the mean orientation along the field direction as a function of the field strength is obtained. Simpler dipole models tend to give misleading results. * Dedicated to W. Vielstich on the occasion of his 60th birthday.

Research paper thumbnail of Electron Transfer Reactions at Oxide Electrodes Involving Tunnelling through a Space Charge Barrier

Berichte der Bunsengesellschaft für physikalische Chemie, 1978

Electron exchange between the conduction band of an oxide electrode and a redox electrolyte in th... more Electron exchange between the conduction band of an oxide electrode and a redox electrolyte in the presence of a space charge barrier is investigated. Two electron transfer mechanisms through the barrier are studied in detail: direct elastic tunnelling and resonance tunnelling via localized states in the band gap. Current/overpotential characteristics are calculated for both mechanisms in dependence on various system parameters such as the Debye length and the band bending. Though the characteristics have a number of features in common, some criteria can be established to distinguish between the two types of tunnelling. The theoretical results are compared with data from several experimental studies; there is evidence that both tunnelling mechanisms occur in real systems.