Tracking Molecular Shear at Metal Surfaces Using Enhanced Lamb Wave Scattering in Plasmonic Nanocavities.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41117547.
- Also identified by DOI 10.1021/acs.nanolett.5c03363 and PMC identifier 12593316.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Extreme plasmonic confinement to the nanoscale can be used to probe the configuration of molecules at metallic surfaces. Exploring low-frequency (<i>h</i>ν < <i>k</i><sub>B</sub><i>T</i>) inelastic light scattering from molecular-monolayer-filled plasmonic nanocavities reveals additional low-frequency excitations not previously observed. We identify these as terahertz Lamb shear modes in the nanogap, exhibiting cross sections even larger than the surface-enhanced Raman scattering (SERS) of the vibrating molecules. Comparing different molecules and metals shows the influence on these Lamb modes of surface binding of the molecular monolayer as well as the strong impact of damping. The large occupation of such modes at room temperature implies their role across many fields, from electrochemistry, molecular electronics, and thermoelectrics to photocatalysis and sensing.