Far-Ultraviolet Plexciton Formation in Water-Covered Indium Clusters.

Area of Science:

• Plasmonics
• Surface Science
• Quantum Chemistry

Background:

• Indium nanoclusters exhibit strong localized surface plasmon polariton (LSP) absorption in the 6-7 eV range.
• Graphene substrates are utilized for fabricating nanoclusters under ultrahigh vacuum conditions.

Purpose of the Study:

• Investigate the formation and properties of plexcitons between indium nanoclusters and water molecules.
• Characterize the coupling strength and spectral evolution of plexcitons in the far-ultraviolet region.
• Determine the decay length of the plexciton collective effect.

Main Methods:

• Fabrication of indium nanoclusters on graphene under ultrahigh vacuum.
• Spectroscopic analysis of nanoclusters before and after water molecule adsorption at 115 K.
• Monitoring spectral changes as a function of water coverage.

Main Results:

• Observed a strong LSP absorption band for indium nanoclusters at 6-7 eV.
• Indium nanocluster/water system exhibited a plexciton band splitting exceeding 1 eV upon water adsorption.
• Determined a decay length of approximately 8 nm for the plexciton collective effect.

Conclusions:

• Demonstrated strong coupling between indium nanocluster LSPs and the water 4a1 ← 1b1 transition.
• The spectral evolution provides insights into plexciton behavior with varying water coverage.
• Established the characteristic decay length of this far-ultraviolet plexciton system.