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Updated: Jun 25, 2026

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

Vibrational excitations in weakly coupled single-molecule junctions: a computational analysis.

Johannes S Seldenthuis¹, Herre S J van der Zant, Mark A Ratner

¹Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.

|February 12, 2009

Summary

This summary is machine-generated.

We developed a new computational method to identify single molecules using their vibrational spectra in low-temperature experiments. This approach accurately predicts vibrational excitation lines, aiding molecular identification in single-molecule junctions.

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Last Updated: Jun 25, 2026

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

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Published on: May 27, 2020

Vibrational Spectra of a N719-Chromophore/Titania Interface from Empirical-Potential Molecular-Dynamics Simulation, Solvated by a Room Temperature Ionic Liquid

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Published on: January 25, 2020

Area of Science:

Physical Chemistry
Molecular Spectroscopy
Quantum Chemistry

Background:

Molecules are typically identified by vibrational spectra using Raman or infrared spectroscopy in bulk systems.
Vibrational excitation lines in low-temperature conductance measurements offer a similar identification method for single-molecule junctions.

Purpose of the Study:

To present an efficient computational method for calculating vibrational excitation lines in single-molecule junctions.
To account for transitions between excited vibrational states, going beyond ground-state to excited-state calculations.

Main Methods:

Combines ab initio density functional theory with rate equations.
Evaluates Franck-Condon factors for multiple vibrational quanta.
Applicable to weakly coupled, gateable single-molecule junctions.

Main Results:

The vibrational spectrum is sensitive to molecular contact geometry and charge state.
Including multiple vibrational quanta is often necessary for accurate predictions.
The method successfully characterizes vibrational excitations in pi-conjugated molecules.

Conclusions:

The developed method can identify single molecules in a junction by analyzing their vibrational spectra.
This computational approach is feasible on standard hardware.
Enables more accurate prediction of vibrational behavior in single-molecule systems.