Coherent Vibrational Dynamics of Au144(SC8H9)60 Nanoclusters
William R Jeffries1, Sami Malola2, Marcus A Tofanelli3
1Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
The Journal of Physical Chemistry Letters
|July 18, 2023
Summary
This study reveals the vibrational dynamics of gold nanoclusters using spectroscopy. Classical models accurately predict these properties, impacting nanotechnologies like sensors.
Area of Science:
- Physical Chemistry
- Materials Science
- Nanotechnology
Background:
- Understanding the vibrational dynamics of metal nanoclusters is crucial for their application in various technologies.
- Gold nanoclusters exhibit unique quantum and classical properties influenced by their size and surface ligands.
Purpose of the Study:
- To investigate the coherent vibrational dynamics of the gold nanocluster Au144(SC8H9)60.
- To compare experimental findings with predictions from classical mechanics models.
- To explore the impact of silver substitution on vibrational properties.
Main Methods:
- Femtosecond time-resolved transient absorption spectroscopy was employed to probe vibrational motions.
- Classical mechanics models were used for theoretical predictions and comparisons.
Main Results:
- Two acoustic modes, breathing (2.0 THz) and quadrupolar (0.7 THz) vibrations, were identified and assigned.
- Experimental results showed excellent agreement with classical model predictions for frequencies, phases, and decoherence times.
- Coherent phonon signals persisted for up to 3 ps, with energy dissipation as the primary dephasing channel.
- Silver substitution did not alter vibrational frequencies but increased inhomogeneous damping.
Conclusions:
- Classical mechanics models accurately describe the vibrational properties of Au144(SC8H9)60.
- Energy dissipation within the nanocluster is the main factor limiting phonon coherence.
- Predicting nanocluster vibrational properties can advance nanoresonator and mass sensing technologies.
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