### Abstract

We analyze the connection between the electron transfer (ET) rate through a given molecular bridge, and the conduction of a junction based on the same bridge between two metals. The Landauer relation between the conduction of a junction and its transmission properties is generalized to yield a relation between conduction and ET rate, including transfer processes dominated by thermal activation. The relation between the orders of magnitude of these observables involves an additional length parameter, of the order of the range of the donor wave function. We find that the functional dependence of these observables on the bridge length (N) and on the temperature (T) changes from the exponential and temperature independent, exp(-βN) for small N, to algebraic and thermally activated form, (α_{1} + α_{2}N)^{-1} exp(-ΔE/k_{B}T), as N increases. An intermediate range of apparent independence on N exists if α_{1} ≫ α_{2}. This behavior is the analogue to the quantum Kramers (barrier crossing) problem, analyzed with respect to the barrier length.

Original language | English |
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Pages (from-to) | 2790-2793 |

Number of pages | 4 |

Journal | Journal of Physical Chemistry B |

Volume | 104 |

Issue number | 13 |

Publication status | Published - Apr 6 2000 |

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### ASJC Scopus subject areas

- Physical and Theoretical Chemistry

### Cite this

*Journal of Physical Chemistry B*,

*104*(13), 2790-2793.

**Activated Conduction in Microscopic Molecular Junctions.** / Segal, Dvira; Nitzan, Abraham; Ratner, Mark A; Davis, William B.

Research output: Contribution to journal › Article

*Journal of Physical Chemistry B*, vol. 104, no. 13, pp. 2790-2793.

}

TY - JOUR

T1 - Activated Conduction in Microscopic Molecular Junctions

AU - Segal, Dvira

AU - Nitzan, Abraham

AU - Ratner, Mark A

AU - Davis, William B.

PY - 2000/4/6

Y1 - 2000/4/6

N2 - We analyze the connection between the electron transfer (ET) rate through a given molecular bridge, and the conduction of a junction based on the same bridge between two metals. The Landauer relation between the conduction of a junction and its transmission properties is generalized to yield a relation between conduction and ET rate, including transfer processes dominated by thermal activation. The relation between the orders of magnitude of these observables involves an additional length parameter, of the order of the range of the donor wave function. We find that the functional dependence of these observables on the bridge length (N) and on the temperature (T) changes from the exponential and temperature independent, exp(-βN) for small N, to algebraic and thermally activated form, (α1 + α2N)-1 exp(-ΔE/kBT), as N increases. An intermediate range of apparent independence on N exists if α1 ≫ α2. This behavior is the analogue to the quantum Kramers (barrier crossing) problem, analyzed with respect to the barrier length.

AB - We analyze the connection between the electron transfer (ET) rate through a given molecular bridge, and the conduction of a junction based on the same bridge between two metals. The Landauer relation between the conduction of a junction and its transmission properties is generalized to yield a relation between conduction and ET rate, including transfer processes dominated by thermal activation. The relation between the orders of magnitude of these observables involves an additional length parameter, of the order of the range of the donor wave function. We find that the functional dependence of these observables on the bridge length (N) and on the temperature (T) changes from the exponential and temperature independent, exp(-βN) for small N, to algebraic and thermally activated form, (α1 + α2N)-1 exp(-ΔE/kBT), as N increases. An intermediate range of apparent independence on N exists if α1 ≫ α2. This behavior is the analogue to the quantum Kramers (barrier crossing) problem, analyzed with respect to the barrier length.

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M3 - Article

VL - 104

SP - 2790

EP - 2793

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

IS - 13

ER -