Raman

Raman spectroscopy is a chemical analysis technique which involves illuminating a substance with a laser and analyzing the light that is scattered off the surface of the substance. The scattered light can provide a lot of information about the substance and its structure, and can be used to identify, characterize, and quantify many chemical components.

The answer has to do with the constant motion of atoms in a molecule, which makes the bonds in atoms kind of like springs that are constantly vibrating in different directions. These molecular vibrations happen at specific frequencies which are unique to the molecule and type of bond. An popular and easy example for such a spring is molecular oxygen (O2) or nitrogen (N2). Imagine each moleccule as two hard spheres connectect by spring of a certain strengths and therefore specific vibrational frequency.

We typically discuss the vibrational frequencies of molecules in terms of wavenumbers, which have units of reciprocal centimeters [cm-1]. So for example, oxygen gas in our atmosphere vibrates at around 1550 cm-1, while nitrogen gas vibrates at 2330 cm-1. Larger molecules with lots of chemical bonds will have many different molecular vibrations occurring at different frequencies.

Now, every time incoming light has the same frequency as the vibration of the molecule, light can be absorbed, “exciting” the vibration further, and amplifying its amplitude. Since the different bonds in molecules vibrate at different frequencies, different molecules will absorb unique frequencies of light to excite vibrations.
So, what do these molecular vibrations have to do with Raman spectroscopy and the inelastic scattering of light? Well, if a molecule is illuminated with light, the molecule may absorb some of that light to excite a molecular vibration. If that happens, the light that scatters off the molecule will come back at a different frequency and color since some of the light from the original beam was absorbed by the molecule. This phenomenon is called the Raman effect, and it’s the cause of Raman scattering.

Raman spectroscopy, like FT-IR spectroscopy, can be used to identify, quantify, and characterize a broad range of substances in industry and in the lab. Additionally, Raman spectroscopy has several unique benefits that cannot be accomplished with other techniques.
Since Raman uses visible laser light, a Raman spectrum can be obtained through any kind of packaging that visible light can go through. This means substances inside glass bottles, plastics bags, or other transparent containers can be analyzed without opening the packaging. The ability to analyze samples inside their packaging is very useful in the pharmaceutical industry for example, where drugs can be checked without contaminating the drug by opening the bottle.

so Raman spectroscopy is a technique used to analyze the chemical structure of a material by shining a laser on it and analyzing the light that scatters back. Our Raman spectrometers empower researchers and scientists with a powerful tool for material analysis. Choose the model that best suits your specific application needs.