Introduction of - Research Paper Example

The paper is going to examine and discuss the function of aniline substituents by looking into the intensities of SERS of different anilines in gold and silver colloids by utilizing a Raman spectrometer which has a 785 nm excitation wavelength. The Chemical Enhancement factors of the Surface Enhanced Raman and detection limits for aniline and its mono- and di-substituted meta derivatives are established and comparisons made. The inductive impacts of withdrawal of electrons as a result of substituents and the steric needs of chemical adsorption influence the strength of signals of different vibrational modes of the aromatic ring and amino group.

By utilizing the transmission electron microscopy (TEM), the level of improvement is also linked to the ways of setting up the silver and gold colloids, which are characterized by exploring the structural morphology of the nanoparticle and its level of aggregation. Introduction: What is Raman Effect? Raman scattering or Raman Effect is the inelastic scattering of photons from an atom or a molecule (Sur, 2010). It was discovered by a well known Indian physicist C V Raman in the year 1928. Generally, most photons are elastically scattered from an atom or a molecule, with the scattered photons having the same energy and wavelength as the incident photons (Sur, 2010).

This phenomenon is known as ‘Rayleigh scattering’ and it accounts for the blue color of the sky (Sur, 2010). There is however a difference in frequency between the scattered photons and the incident photons. This physicist discovered the Raman Effect as he was working on the molecular diffraction of light and observed this effect in liquid. The Other Russian scientists Gregory Landsberg and Leonid Mandelstam first observed this effect in crystals (Sur, 2010). Raman won the Nobel Prize in 1930 for his work on inelastic scattering of photons.

The history of SERS SERS was discovered accidentally in 1974 as people attempted to perform Raman on the electrode with an original idea of generating a high surface area on that extremely roughened metal. With time, people realized that the surface area was not the fundamental point on this arena. Periodical searches were made in the dark, which led to progress in 1977 when different groups found out that the rough silver electrode can produce a Raman spectrum that is a million fold more intense than what was expected (Ferraro, 1994).

The huge signal confirmed surface enhanced Raman scattering (SERS). SERS have recently overcome the disadvantage of the small cross section of Raman spectroscopy completely, and therefore can be utilized to study the single molecule spectroscopy (Ferraro, 1994). Surface-enhanced Raman spectroscopy (SERS) has experienced renaissance recently in its development as a result of the remarkable discovery of single molecule SERS (SMSERS). This has also led to the explosion of interest in nanophotonics and plasmonics (Dieringer, 2005).

Since excitation of the localized surface Plasmon resonance (LSPR) of a nanostructured surface or nanoparticle Is centered at the heart of SERS, it is vital to have in control all of the factors influencing the LSPR with an aim to maximize signal strength and ensure reproducibility (Dieringer, 2005)