Gauging Molecular Orientation through Time Domain Simulations of Surface-Enhanced Raman Scattering

Journal Article · Thu Aug 15 04:00:00 EDT 2019 · Journal of Physical Chemistry A

DOI:https://doi.org/10.1021/acs.jpca.9b06182· OSTI ID:1734860

Apra, Edoardo ^[1]; Bhattarai, Ashish ^[1]; El-Khoury, Patrick Z. ^[1]

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1. BATTELLE (PACIFIC NW LAB)

Molecular re-orientation dynamics modulate the physical and chemical properties of molecules at interfaces. This is particularly the case for organic molecules interacting with metallic surfaces - structural motifs of current interest to ultrasensitive chemical/biological detection/imaging. In this context, surface-enhanced Raman scattering (SERS) can be used to gauge the orientation of molecules in the immediate vicinity of plasmonic metals. Herein, we analyze SERS spectra of two aromatic thiols (4-mercaptobenzonitrile and thiophenol) chemisorbed onto silver substrates using ab initio molecular dynamics (AIMD)-based Raman spectral simulations that account for the optical response of molecules in the bulk and oriented molecules at the surface. Through a comparison with prior works aimed at gauging the orientation of our two model systems on metallic substrates, we describe the advantages and discuss the limitations of our described models and approach to gauging the orientation of molecules on metals through time-domain simulations of their SERS signatures.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1734860
• Report Number(s): PNNL-SA-145212
• Journal Information: Journal of Physical Chemistry A, Journal Name: Journal of Physical Chemistry A Journal Issue: 32 Vol. 123
• Country of Publication: United States
• Language: English