Question

Choose one of the following spectroscopy fields and use the book/internet, to describe its principle (3-5 sentences) and applications (at least one example). (5 points each aspect, 10 points total) Rotational spectroscopy; Raman; Photoelectron; Fluorescence; Electronic; Vibrational; UV-Vis; or your own choice other than NMR

Answer 1

Vibrational spectroscopy is a non-destructive identification method that measures the vibrational energy in a compound. Each chemical bond has a unique vibrational energy. Even a carbon-carbon bond will be different from one compound to another depending on what other compounds each carbon is bound to.

What Is Vibrational Spectroscopy?

How do we identify an unknown substance or ensure a specific substance is what we think? There are several ways to do this that will destroy the sample, which unfortunately means further testing cannot be performed on it. Vibrational spectroscopy is a non-destructive identification method that measures the vibrational energy in a compound.

Each chemical bond has a unique vibrational energy. Even a carbon-carbon bond will be different from one compound to another depending on what other compounds each carbon is bound to. Due to this unique vibrational energy, each compound will have a unique fingerprint , or the output identifying the peak strengths at specific vibrations. This fingerprint can be used to determine compound structures, identify and characterize compounds, and identify impurities. This is done by comparing the fingerprint with the fingerprints of known compounds.

There are two types of vibrational spectroscopy: infrared and Raman. The main difference between these is the types of vibrations and transitions that are measured. Typically these two forms will be used in connection with each other in order to get a more complete picture of the compounds.

APPLICATION =

Vibrational spectroscopy is used to study a very wide range of sample types and can be carried out from a simple identification test to an in-depth, full spectrum, qualitative, and quantitative analysis. Samples may be examined either in bulk or in microscopic amounts over a wide range of temperatures and physical states (e.g., gases, liquids, latexes, powders, films, fibers, or as a surface or embedded layer). Vibrational spectroscopy has a very broad range of applications and provides solutions to a host of important and challenging analytical problems.

EXAMPLE

To determine the vibrational spectroscopy of linear molecules, the rotation and vibration of linear molecules are taken into account to predict which vibrational (normal) modes are active in the infrared spectrum and the Raman spectrum .