Holmarc's CCD Based Laser Raman Spectrometer apparatus (Model No: HO-ED-S-06A) is an apparatus designed for recording Raman spectra of both solids and liquid samples. Raman spectroscopy is a scattering technique. It is based on Raman Effect, i.e., frequency of a small fraction of scattered radiation is different from frequency of monochromatic incident radiation.
It is based on the inelastic scattering of incident radiation through its interaction with vibrating molecules. It probes the molecular vibrations. This will produce a different range of frequencies, namely intense stokes and anti stokes, which have higher frequency than the incident radiation along Rayleigh line. Rayleigh and Raman scattering can be explained both classically and quantum mechanically.
In CCD based Raman spectrometer, sample is kept in cuvette accompanied by the mechanical chamber with DPSS laser (532nm). The vibrational state of molecule while relaxing the high energy state re-emits the radiation in all directions. Spectrometer is positioned in such a way that laser beam collide at the cuvette perpendicularly. Notch filter is used in front of the spectrometer to avoid Rayleigh scattering so that Raman radiations are measured efficiently.
Highly sensitive (0.1 -6500ms), low noise, cooled CCD is ideal as a detector for Raman spectrum studies. Czerny Turner design is applied in the spectrometer with precision holographic grating as dispersion element. The control electronic devices convert the optical dispersion to electronic pulses which is transmitted to computer via USB.
The software used to interpret the data is user friendly. Regression / curve fit algorithms ( Newton - Raphson numerical analysis, Levenberg Marquardt algorithms, etc ) are used. Savitzky – Golay filtering / Box car smoothing purposes, etc are the features of the software. Material library is provided for customized versions.