What is Resonance Raman Spectroscopy?

Raman spectroscopy is an analytical method fundamentally concerned with inelastically scattered light, which indicates a critical interaction between light and matter. This information is crucial for many applications. By examining the scattered light, analysts can obtain in-depth details about a sample's chemical structure and molecular interactions. This technique provides numerous benefits to its intended applications. However, it can be drastically improved by using resonance Raman spectroscopy. This blog post will overview resonance Raman spectroscopy and its applications.  

What is Resonance Raman Spectroscopy?

Resonance Raman spectroscopy (RR spectroscopy) is based on the analytical technique of Raman spectroscopy and is used to significantly improve the effects of Raman scattering (by a factor of 102-106.  In resonance Raman spectroscopy, the critical consideration is the chosen excitation wavelength because resonance Raman scattering can only occur when the laser excitation frequency is similar to the electronic transition of the sample in question. Effectively, the laser wavelength must correspond to where the molecule in question absorbs light strongly. The name of this method comes from the laser light frequency ‘resonating’ with the electronic sample, which is when the optimal level of enhancement happens. 

The benefits of using resonance Raman spectroscopy include having a shorter exposure time, which allows spectra to be acquired much faster, improved signal-to-noise and greater sensitivity. Another advantage is that a standard Raman microscope can be used for this method, but with an adjusted light source and an adjusted wavelength.

Applications of Resonance Raman Spectroscopy

Resonance Raman spectroscopy is a selective analytical method that benefits many applications, namely those with low-concentration samples and when Raman spectra of short-lived excited state species need to be analyzed. When studying biological species, Resonance Raman can be used to identify the chemical composition of solids and liquids and, in many cases, gases.

Some of the typical applications include:

  • Analysis of colored samples
  • Analysis of proteins and other biomolecules
  • Blood cell analysis
  • Drug discovery
  • Monitoring the structure of proteins in solution

Interestingly, resonance Raman spectroscopy is also used for applications outside the science industries, such as archaeology and art, due to the abovementioned benefits.

Analyzing Biomolecules

In resonance Raman spectroscopy, a subset of vibrations will be localized on the resonant chromophore. These vibrations take up a large part of the resonance Raman spectrum and enable heightened sensitivity, making RR spectroscopy an ideal solution for studying crowded and complex molecules, such as proteins and other biomolecules. 

Blood Cell Analysis

Because of the enhanced spectral features that resonance Rama spectroscopy offers, it has become an excellent method for analyzing blood and blood-related samples. It is a non-invasive method that can characterize samples and measure the levels of electrolytes, nutrients and waste in the blood.

CRAIC Technologies and Resonance Raman Spectroscopy

CRAIC Technologies™ designs and manufactures a wide range of scientific instruments that can be used across several industries. These instruments are powerful tools used in numerous applications in the research and industry fields, and we have designed them with flexible packages to suit your requirements. 


If you’re looking to purchase a Raman microspectrometer or want more information about the applications of resonance Raman spectroscopy, please don’t hesitate to contact us.