On the chemical bonding effects in the Raman response: benzenethiol adsorbed on silver clusters.

نویسندگان

  • Semion K Saikin
  • Roberto Olivares-Amaya
  • Dmitrij Rappoport
  • Michael Stopa
  • Alán Aspuru-Guzik
چکیده

We study the effects of chemical bonding on Raman scattering from benzenethiol chemisorbed on silver clusters using time-dependent density functional theory (TDDFT). Raman scattering cross sections are computed using a formalism that employs analytical derivatives of frequency-dependent electronic polarizabilities, which treats both off-resonant and resonant enhancement within the same scheme. In the off-resonant regime, Raman scattering into molecular vibrational modes is enhanced by one order of magnitude and shows pronounced dependence on the orientation and the local symmetry of the molecule. Additional strong enhancement of the order of 10(2) arises from resonant transitions to mixed metal-molecular electronic states. The Raman enhancement is analyzed using Raman excitation profiles (REPs) for the range of excitation energies 1.6-3.0 eV, in which isolated benzenethiol does not have electronic transitions. The computed vibrational frequency shifts and relative Raman scattering cross sections of the metal-molecular complexes are in good agreement with experimental data on surface enhanced Raman scattering (SERS) from benzenethiol adsorbed on silver surfaces. Characterization and understanding of these effects, associated with chemical enhancement mechanism, may be used to improve the detection sensitivity in molecular Raman scattering.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

On the chemical bonding effects in the Raman response: Benzenethiol adsorbed on silver clusterswz

We study the effects of chemical bonding on Raman scattering from benzenethiol chemisorbed on silver clusters using time-dependent density functional theory (TDDFT). Raman scattering cross sections are computed using a formalism that employs analytical derivatives of frequency-dependent electronic polarizabilities, which treats both off-resonant and resonant enhancement within the same scheme. ...

متن کامل

Raman Study of the Photochemistry of Maleic Acid Adsorbed on the Surface of Colloidal Silver

The surface-enhanced Raman scattering (SERS) spectra of maleic (cis; 2-butaneoic acid) and fumaric (trans; 2-butaneoic acid) acids adsorbed on aqueous silver sol particles are reported. These two acids form two groups of isomers which differ only in the relative positions of the two carboxylate groups. The photochemistry of maleic and fumaric acids adsorbed on the surface of silver colloids...

متن کامل

Surface-enhanced Raman spectroscopy of benzenethiol adsorbed from the gas phase onto silver film over nanosphere surfaces: determination of the sticking probability and detection limit time.

A chemical warfare agent (CWA) gas detector based on surface-enhanced Raman spectroscopy (SERS) using robust nanostructured substrates and a portable Raman spectrometer is a promising alternative to existing modalities. A gas-dosing apparatus was constructed to simulate chemical gas exposure and provide a platform for quantitative analysis of SERS detection. As a first step toward characterizin...

متن کامل

Rigorous surface enhanced Raman spectral characterization of large-area high-uniformity silver-coated tapered silica nanopillar arrays.

Surface enhanced Raman spectroscopy (SERS) has been increasingly utilized as an analytical technique with significant chemical and biological applications (Qian et al 2008 Nat. Biotechnol. 26 83; Fujita et al 2009 J. Biomed. Opt. 14 024038; Chou et al 2008 Nano Lett.8 1729; Culha et al 2003 Anal. Chem. 75 6196; Willets K A 2009 Anal. Bioanal. Chem. 394 85; Han et al 2009 Anal. Bioanal. Chem. 39...

متن کامل

Surface Enhanced Raman Spectroscopy of Halide Ions on Colloidal Silver: Morphology and Coverage Dependence

Transmission electron microscopy shows that the colloidal silver used as a substrate for surface enhanced Raman spectroscopy consists of 75-135 .~ average diameter faceted crystals, which can be made to aggregate in clusters of a few to thousands of particles. Aggregates are not required for observation of the SER spectrum of adsorbed halide ions or pyridine. Bromide is shown to adsorb more rea...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • Physical chemistry chemical physics : PCCP

دوره 11 41  شماره 

صفحات  -

تاریخ انتشار 2009