iSpecRaman-HH	iSpecRaman-785	iSpecMS-Raman785

Main Technical Indicators

Raman spectroscopy is based on the scattering of light by molecules, associated with changes in the vibrational and rotational energy levels resulting from changes in molecular polarizability. It occurs due to symmetric vibrations of bonds with symmetric charge distributions, such as -C=C-, -N=N-, and -S-S-, where the dipole moment remains unchanged during vibration. By stimulating molecular motion with light and interpreting this interaction, chemical analysis of samples is possible. Raman spectroscopy is frequently used to investigate the symmetric vibrations of non-polar groups and backbones.

An energy level diagram visually displays various energy levels corresponding to Raman signals, with line thickness roughly indicative of signal magnitude.

The Raman effect happens when light interacts with electron clouds and molecular bonds, leading to spontaneous Raman scattering. This phenomenon excites molecules from the ground state to a virtual energy state. When these excited molecules emit a photon and return to a different state from the ground state—either rotational or vibrational—the energy difference between these states results in the emitted photon having a frequency different from that of the excitation light.

Basic Principles of Single-Beam Electron Resonance Enhanced Coherent Raman Scattering

Raman Measurement Solutions

To obtain a Raman spectrum, simply focus a laser on the sample. The sample under the excitation laser must not produce fluorescence. If fluorescence occurs, it will mask the majority of the Raman effect, as the fluorescence signal is significantly stronger than the Raman signal. After the laser irradiates the sample, the scattered light passes through a filter to remove any light from the excitation laser. This light is then directed onto a grating, which, like a prism, disperses the inelastically scattered light according to wavelength. Finally, these light rays are directed to a CCD sensor, which creates a spectrum based on the intensity.

Raman Measurement Setup Diagram

Raman Connection Diagram

Raman spectroscopy is valuable for both qualitative and quantitative analyses. The Raman spectrum, featuring peak positions and relative intensities, provides a unique chemical fingerprint that can identify a substance and distinguish it from others. Practical testing of Raman spectra can be complex, especially when peak attribution for unknown substances is challenging. Utilizing a Raman spectroscopy database for matching can expedite the identification process of unknown substances.

Software Interface

In the field of chemistry, chemical bonds and symmetric molecules have specific vibrational spectral information, making them crucial for molecular identification. For instance, the vibrational frequencies of SiO, Si2O2, and Si3O3 can be identified and are fundamental to studies in infrared spectroscopy and Raman spectroscopic coordination analysis.

Raman Spectrum of Dimethyl Silicone Sample (Blue) Compared to Spectral Library

Raman Spectra of Sodium Cobalt Nitrite Solution (Blue) & Sodium Potassium Cobalt Nitrite (Red)