*2.4.1 Principle*

Raman spectroscopy based on the scattering of light, which was described by C.V. Raman in 1928 through his outstanding study i.e., Raman effect. According to Raman effect when a certain frequency of monochromatic radiations incident on a sample, the incident light is scattered through interaction with vibrating sample molecules, the frequency of scattered light is different from that of the incident light. It is based on the inelastic scattering of incident radiation [27]. In Raman spectroscopy, when a monochromatic radiation strikes the sample, it scatters in all directions after its interaction with sample molecules. Much of this scattered radiation elastically that constitutes Rayleigh scattering. Only a small fraction of scattered radiation in-elastically scattered that constitutes Raman

**Figure 12.** *FTIR spectrum of Sparfloxacin.*

*Spectroscopy and Spectrophotometry: principles and Applications for Colorimetric and Related… DOI: http://dx.doi.org/10.5772/intechopen.101106*

scattering. Usually, in Raman spectrum there is an appearance of Stokes lines, this is due to the frequency of incident radiation is higher than frequency of scattered radiation. On the other hand, there is an appearance of anti-Stokes lines in Raman spectrum, when the frequency of incident radiation is lower than frequency of scattered radiation occurs.
