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Synthesis and Characterization of Supramolecular Colloids
Published on: April 22, 2016
Formation of core-shell silver-ethane clusters in He droplets
Evgeny Loginov1, Luis F Gomez, Andrey F Vilesov
1Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States.
The Journal of Physical Chemistry. A
|June 18, 2013
Summary
Large helium droplets facilitate the creation of silver-ethane clusters. Infrared spectroscopy reveals ethane molecules near silver exhibit a frequency shift, indicating structural changes in larger clusters.
Area of Science:
- Atomic and molecular physics
- Cluster science
- Spectroscopy
Background:
- Helium droplets are valuable tools for studying weakly interacting systems.
- Composite clusters offer insights into surface interactions and material properties.
Purpose of the Study:
- To investigate the formation and structure of silver-ethane composite clusters grown in helium droplets.
- To analyze the structural transitions of silver clusters using ethane as a molecular probe.
Main Methods:
- Assembly of silver-ethane clusters by sequential doping of helium droplets.
- Infrared spectroscopy to probe the C-H stretch region of ethane molecules.
- Analysis of spectral band shifts and intensity ratios to determine cluster structure.
Main Results:
- Ethane molecules at the silver-ethane interface show a 15 cm(-1) low-frequency shift in the ν7 band.
- A dense core-shell model accurately describes clusters with <100 atoms.
- Large silver clusters (~3000 atoms) exhibit a ramified structure, with 5x larger surface area than predicted by the core-shell model.
- Helium droplets function as calorimeters for measuring captured species and absorbed laser energy.
Conclusions:
- Helium droplet encapsulation enables the study of composite cluster formation and structure.
- The observed structural transition in silver clusters provides insights into growth mechanisms.
- Helium droplets serve as versatile tools for both cluster synthesis and in-situ metrology.
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