Vibrational excitations in weakly coupled single-molecule junctions

A computational analysis

Johannes S. Seldenthuis, Herre S J van der Zant, Mark A Ratner, Joseph M. Thijssen

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

In bulk systems, molecules are routinely identified by their vibrational spectrum using Raman or infrared spectroscopy. In recent years, vibrational excitation lines have been observed in low-temperature conductance measurements on single-molecule junctions, and they can provide a similar means of identification. We present a method to efficiently calculate these excitation lines in weakly coupled, gateable single-molecule junctions, using a combination of ab initio density functional theory and rate equations. Our method takes transitions from excited to excited vibrational state into account by evaluating the Franck-Condon factors for an arbitrary number of vibrational quanta and is therefore able to predict qualitatively different behavior from calculations limited to transitions from ground state to excited vibrational state. We find that the vibrational spectrum is sensitive to the molecular contact geometry and the charge state, and that it is generally necessary to take more than one vibrational quantum into account. Quantitative comparison to previously reported measurements on π-conjugated molecules reveals that our method is able to characterize the vibrational excitations and can be used to identify single molecules in a junction. The method is computationally feasible on commodity hardware.

Original languageEnglish
Pages (from-to)1445-1451
Number of pages7
JournalACS Nano
Volume2
Issue number7
DOIs
Publication statusPublished - Jul 2008

Fingerprint

Molecules
excitation
molecules
Vibrational spectra
vibrational states
vibrational spectra
commodities
Electron transitions
Ground state
Density functional theory
Raman spectroscopy
Infrared spectroscopy
hardware
infrared spectroscopy
density functional theory
Hardware
ground state
Geometry
geometry
Temperature

Keywords

  • Coulomb blockade
  • Density functional theory
  • Franck-Condon factors
  • Rate equations
  • Single-molecule junction
  • Three-terminal transport
  • Vibrational modes

ASJC Scopus subject areas

  • Engineering(all)
  • Materials Science(all)
  • Physics and Astronomy(all)

Cite this

Vibrational excitations in weakly coupled single-molecule junctions : A computational analysis. / Seldenthuis, Johannes S.; van der Zant, Herre S J; Ratner, Mark A; Thijssen, Joseph M.

In: ACS Nano, Vol. 2, No. 7, 07.2008, p. 1445-1451.

Research output: Contribution to journalArticle

Seldenthuis, Johannes S. ; van der Zant, Herre S J ; Ratner, Mark A ; Thijssen, Joseph M. / Vibrational excitations in weakly coupled single-molecule junctions : A computational analysis. In: ACS Nano. 2008 ; Vol. 2, No. 7. pp. 1445-1451.
@article{5eb2f8603d504f67ae5f89572c6690a9,
title = "Vibrational excitations in weakly coupled single-molecule junctions: A computational analysis",
abstract = "In bulk systems, molecules are routinely identified by their vibrational spectrum using Raman or infrared spectroscopy. In recent years, vibrational excitation lines have been observed in low-temperature conductance measurements on single-molecule junctions, and they can provide a similar means of identification. We present a method to efficiently calculate these excitation lines in weakly coupled, gateable single-molecule junctions, using a combination of ab initio density functional theory and rate equations. Our method takes transitions from excited to excited vibrational state into account by evaluating the Franck-Condon factors for an arbitrary number of vibrational quanta and is therefore able to predict qualitatively different behavior from calculations limited to transitions from ground state to excited vibrational state. We find that the vibrational spectrum is sensitive to the molecular contact geometry and the charge state, and that it is generally necessary to take more than one vibrational quantum into account. Quantitative comparison to previously reported measurements on π-conjugated molecules reveals that our method is able to characterize the vibrational excitations and can be used to identify single molecules in a junction. The method is computationally feasible on commodity hardware.",
keywords = "Coulomb blockade, Density functional theory, Franck-Condon factors, Rate equations, Single-molecule junction, Three-terminal transport, Vibrational modes",
author = "Seldenthuis, {Johannes S.} and {van der Zant}, {Herre S J} and Ratner, {Mark A} and Thijssen, {Joseph M.}",
year = "2008",
month = "7",
doi = "10.1021/nn800170h",
language = "English",
volume = "2",
pages = "1445--1451",
journal = "ACS Nano",
issn = "1936-0851",
publisher = "American Chemical Society",
number = "7",

}

TY - JOUR

T1 - Vibrational excitations in weakly coupled single-molecule junctions

T2 - A computational analysis

AU - Seldenthuis, Johannes S.

AU - van der Zant, Herre S J

AU - Ratner, Mark A

AU - Thijssen, Joseph M.

PY - 2008/7

Y1 - 2008/7

N2 - In bulk systems, molecules are routinely identified by their vibrational spectrum using Raman or infrared spectroscopy. In recent years, vibrational excitation lines have been observed in low-temperature conductance measurements on single-molecule junctions, and they can provide a similar means of identification. We present a method to efficiently calculate these excitation lines in weakly coupled, gateable single-molecule junctions, using a combination of ab initio density functional theory and rate equations. Our method takes transitions from excited to excited vibrational state into account by evaluating the Franck-Condon factors for an arbitrary number of vibrational quanta and is therefore able to predict qualitatively different behavior from calculations limited to transitions from ground state to excited vibrational state. We find that the vibrational spectrum is sensitive to the molecular contact geometry and the charge state, and that it is generally necessary to take more than one vibrational quantum into account. Quantitative comparison to previously reported measurements on π-conjugated molecules reveals that our method is able to characterize the vibrational excitations and can be used to identify single molecules in a junction. The method is computationally feasible on commodity hardware.

AB - In bulk systems, molecules are routinely identified by their vibrational spectrum using Raman or infrared spectroscopy. In recent years, vibrational excitation lines have been observed in low-temperature conductance measurements on single-molecule junctions, and they can provide a similar means of identification. We present a method to efficiently calculate these excitation lines in weakly coupled, gateable single-molecule junctions, using a combination of ab initio density functional theory and rate equations. Our method takes transitions from excited to excited vibrational state into account by evaluating the Franck-Condon factors for an arbitrary number of vibrational quanta and is therefore able to predict qualitatively different behavior from calculations limited to transitions from ground state to excited vibrational state. We find that the vibrational spectrum is sensitive to the molecular contact geometry and the charge state, and that it is generally necessary to take more than one vibrational quantum into account. Quantitative comparison to previously reported measurements on π-conjugated molecules reveals that our method is able to characterize the vibrational excitations and can be used to identify single molecules in a junction. The method is computationally feasible on commodity hardware.

KW - Coulomb blockade

KW - Density functional theory

KW - Franck-Condon factors

KW - Rate equations

KW - Single-molecule junction

KW - Three-terminal transport

KW - Vibrational modes

UR - http://www.scopus.com/inward/record.url?scp=49249099755&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=49249099755&partnerID=8YFLogxK

U2 - 10.1021/nn800170h

DO - 10.1021/nn800170h

M3 - Article

VL - 2

SP - 1445

EP - 1451

JO - ACS Nano

JF - ACS Nano

SN - 1936-0851

IS - 7

ER -