Campus Units
Ames Laboratory, Chemistry
Document Type
Article
Publication Version
Published Version
Publication Date
4-13-2012
Journal or Book Title
Analytical Chemistry
Volume
84
Issue
10
First Page
4300
Last Page
4306
DOI
10.1021/ac203355a
Abstract
Total internal reflection (TIR) Raman and reflectivity spectra were collected for nonresonant analytes as a function of incident angle at sapphire or sapphire/smooth 50 nm gold interfaces using 785 nm excitation. For both interfaces, the Raman signal as a function of incident angle is well-modeled by the calculated interfacial mean square electric field (MSEF) relative to the incident field times the thickness of the layer being probed in the Raman measurement (DRS). The Raman scatter was reproducibly enhanced at the interface containing a gold film relative to the sapphire interface by a factor of 4.3−4.6 for aqueous pyridine or 2.2−3.7 for neat nitrobenzene, depending on the analyzed vibrational mode. The mechanism for the increased Raman signal is the enhanced MSEF at incident angles where propagating surface plasmons are excited in the metal film. The background from the TIR prism was reduced by 89−95% with the addition of the gold film, and the percent relative uncertainty in peak area was reduced from 15 to 1.7% for the 1347 cm−1 mode of nitrobenzene. Single monolayers of benzenethiol (S/N = 6.8) and 4-mercaptopyridine (S/N = 16.5) on gold films were measured by TIR Raman spectroscopy with 785 nm excitation (210 mW) without resonant enhancement in 1 min.
Copyright Owner
American Chemical Society
Copyright Date
2012
Language
en
File Format
application/pdf
Recommended Citation
McKee, Kristopher J.; Meyer, Matthew W.; and Smith, Emily A., "Near IR Scanning Angle Total Internal Reflection Raman Spectroscopy at Smooth Gold Films" (2012). Chemistry Publications. 906.
https://lib.dr.iastate.edu/chem_pubs/906
Included in
Analytical Chemistry Commons, Medicinal-Pharmaceutical Chemistry Commons, Other Chemistry Commons, Physical Chemistry Commons
Comments
Reprinted (adapted) with permission from Analytical Chemistry, 84(10); 4300-4306. Doi: 10.1021/ac203355a. Copyright 2012 American Chemical Society.