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Spectroscopy of the copper dimer in normal fluid, superfluid, and solid (4)He
V Lebedev1, P Moroshkin, J P Toennies
1Department of Physics, University of Fribourg, Chemin du Musée 3, 1700 Fribourg, Switzerland.
The Journal of Chemical Physics
|October 26, 2010
Summary
Copper dimers (Cu2) in helium show distinct vibrational spectra. The spectra remained unchanged across different helium phases (superfluid, normal liquid, solid), suggesting weak interactions with the helium matrix.
Area of Science:
- Physical Chemistry
- Spectroscopy
- Condensed Matter Physics
Background:
- Laser ablation is a technique used to generate atomic and molecular species.
- Condensed helium provides a unique matrix for studying molecular properties.
- Diatomic copper (Cu2) spectroscopy reveals insights into molecular interactions.
Purpose of the Study:
- To investigate the spectroscopic properties of copper dimers in condensed helium.
- To understand the influence of helium's phase and pressure on Cu2 spectra.
- To compare Cu2 interactions in helium with those in other rare gas matrices.
Main Methods:
- Laser ablation of copper into liquid and solid helium.
- Observation of emission spectra for Cu2 (D→X, B→X, a→X transitions).
- Variable temperature and pressure conditions for helium (superfluid, normal liquid, solid).
Main Results:
- Clearly resolved vibrational bands were observed for Cu2 transitions.
- Spectra showed no significant differences across superfluid, normal liquid, and solid helium phases.
- Line shifts and widths in helium were an order of magnitude smaller than in other solid rare gas matrices.
Conclusions:
- The interaction between Cu2 and the helium matrix is significantly weaker than with alkali atoms.
- The bubble model provides a suitable interpretation for the observed weak interactions.
- Condensed helium offers a unique, low-interaction environment for molecular spectroscopy.
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