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How do adsorbent orientation and direction of external electric field affect the charge-transfer surface-enhanced raman spectra?

Ashtari Jafari, S ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1021/acs.jpcc.1c02319
  3. Publisher: American Chemical Society , 2021
  4. Abstract:
  5. Surface-enhanced Raman spectroscopy is a highly sensitive phenomenon and a powerful fingerprint detection tool that reflects the small changes in polarizability on the pattern and intensity of Raman signals. The SERS enhancement signals elucidate with the surface-selection rules. In this regard, molecular configuration and adsorption orientation on the surface, in addition to the direction of external electric field, can lead to different patterns of SERS spectra. To evaluate how the variation of these features influences the pattern and reproducibility of the spectra, the chemical charge-transfer SERS spectra for pyridine on silver clusters are calculated for different field directions, tilt angles, and anchoring bond distances. The impact of external electric field direction versus the adsorbed tilt angle and Ag-N bond distance on the pattern of SERS-CT spectra is established by time-dependent excited-state gradient approximation and elucidated based on the deviation of ground- and excited-state properties from the optimized condition. © 2021 American sChemical Society
  6. Keywords:
  7. Charge transfer ; Electric fields ; Molecular orientation ; Pattern recognition ; Raman spectroscopy ; Silver compounds ; Excited-state properties ; External electric field ; Fingerprint detections ; Molecular configurations ; Optimized conditions ; Reproducibilities ; Surface enhanced Raman spectroscopy ; Surface selection ; Excited states
  8. Source: Journal of Physical Chemistry C ; Volume 125, Issue 24 , 2021 , Pages 13382-13390 ; 19327447 (ISSN)
  9. URL: https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.1c02319