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Double and triple ionization of silver clusters by electron impact
Avik Halder1, Anthony Liang, Chunrong Yin
1Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484, USA.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|February 23, 2012
Summary
This study investigates the ionization of silver clusters, finding that higher charge states appear at lower energies than expected. This behavior in silver cluster cations suggests complex ionization mechanisms requiring further research.
Area of Science:
- Physical Chemistry
- Atomic and Molecular Physics
- Materials Science
Background:
- Noble metal clusters exhibit unique properties influenced by size and charge.
- Understanding ionization processes in silver clusters is crucial for materials science applications.
Purpose of the Study:
- To investigate the production of silver cluster cations Ag(n)(2+) and Ag(n)(3+) via electron impact ionization.
- To analyze the scaling of appearance energies with cluster radius and compare it with existing models.
Main Methods:
- Electron impact ionization of neutral silver cluster precursors.
- Measurement of appearance energies for different silver cluster cation sizes (Ag(n)(2+), Ag(n)(3+)).
Main Results:
- Appearance energy scaling with cluster radius deviates from predictions for single ionization and smaller doubly charged ions.
- Yield of high-charge cations (Ag(n)(2+), Ag(n)(3+)) increases faster than singly charged ions (Ag(n)(+)) with rising electron energy.
- Observed ionization behavior aligns with power-law dependence in post-threshold ionization.
Conclusions:
- The metallic droplet model partially describes appearance energy scaling but requires modification for multiple ionization.
- Observed ionization trends suggest complex mechanisms in noble metal clusters.
- Further experimental and theoretical studies are needed to fully elucidate multiple ionization phenomena in silver clusters.
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