Journal article
Sum-Frequency Spectroscopy of Molecular Adsorbates on Low-Index Ag Surfaces: Effects of Azimuthal Rotation
Analytical chemistry (Washington), Vol.81(3), pp.1154-1161
02/01/2009
DOI: 10.1021/ac802332h
PMID: 19115941
Abstract
Vibrational sum-frequency generation spectroscopy (SFG) lineshapes of p-cyanobenzenethiol on low-index Ag crystal surfaces are studied as a function of azimuthal rotation by angle ϕ. A broadband multiplex SFG method is used, with a new technique that variably suppresses the non-resonant (NR) background using time-asymmetric time-delayed picosecond laser pulses. When both resonant (R) and NR signals are present, the amplitude and phase of the R line shape can vary significantly with ϕ, leading to dramatic ϕ-dependent variations of the SFG spectrum. The CN-stretch transition of p-cyanobenzenethiol modified Ag(111) and Ag(110) surfaces has an SFG spectrum consisting of a single vibrational resonance R atop a NR background that originates from the metal surface. Using the NR suppression technique, it was found that the R amplitude of the CN-stretch was independent of ϕ on both Ag(111) and Ag(110), which proves that the CN dipole moment is parallel to the surface normal in both cases. We show that it is possible to accurately extract the ϕ-dependence of the R amplitude, the NR amplitude, and the phase difference from SFG spectra by suppressing the NR signal during sample roation, thereby proving that the R contribution from the CN-stretch transition evidence ϕ-invariant behavior on both Ag surfaces.
Details
- Title: Subtitle
- Sum-Frequency Spectroscopy of Molecular Adsorbates on Low-Index Ag Surfaces: Effects of Azimuthal Rotation
- Creators
- Scott K ShawAlexei LagutchevDana D DlottAndrew A Gewirth
- Resource Type
- Journal article
- Publication Details
- Analytical chemistry (Washington), Vol.81(3), pp.1154-1161
- Publisher
- American Chemical Society
- DOI
- 10.1021/ac802332h
- PMID
- 19115941
- ISSN
- 0003-2700
- eISSN
- 1520-6882
- Language
- English
- Date published
- 02/01/2009
- Academic Unit
- Chemistry
- Record Identifier
- 9983985936302771
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