The Raman effect is the appearance of weak lines in the spectrum of light scattered by a substance which has been illuminated by a monochromatic light (with angular frequency ω).The lines occur close to, and on each side of, the incident light frequency, and hence are optical sidebands. The sidebands arise from the nonlinear interaction of the light with atomic or molecular quantum states in the scattering material. Because this theory was invented by sir C.V. Raman and he got the noble prize for that in physics.

1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 83-89 © IAEME
83
A REVIEW ON RAMAN EFFECT ITS APPLICATIONS AND SPECTRUM &
TO STUDY INFRARED AND RAMAN SPECTROSCOPY
Dr GURUDUTT SAHNIa
, BALPREET SINGHb
a
(HOD & DGM (Design, Drawing & Development) LEADER VALVES LTD JALANDHAR,
PUNJAB, INDIA) & C Eng (INSTITUTION OF ENGINEERS INDIA)
b
(SCHOLAR, DEPTT OF MECH ENGG (100101128373) BEANT COLLEGE OF ENGG & TECH
GURDASPUR, PUNJAB, INDIA)
ABSTRACT
The Raman effect is the appearance of weak lines in the spectrum of light scattered by a
substance which has been illuminated by a monochromatic light (with angular frequency ω).The
lines occur close to, and on each side of, the incident light frequency, and hence are optical
sidebands. The sidebands arise from the nonlinear interaction of the light with atomic or molecular
quantum states in the scattering material. Because this theory was invented by sir C.V. Raman and he
got the noble prize for that in physics. The phenomenon is named for Indian physicist Sir
ChandrasekharaVenkata Raman, who first published observations of the effect in 1928. (Austrian
physicist Adolf Smekal theoretically described the effect in 1923.
MAIN OBJECTIVES ARE
1. TO STUDY RAMAN EFFECT
2. TO STUDY INFRARED AND RAMAN SPECTROSCOPY
3. TO STUDY APPLICATIONS OF RAMAN SPECTROSCOPY
4. TO STUDY RAMAN SPECTRUM AND ADVANTAGES
Keywords: RAMAN, SPECTROSCOPY.
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ISSN 0976 – 6340 (Print)
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Volume 5, Issue 4, April (2014), pp. 83-89
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2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 83-89 © IAEME
84
INTRODUCTION
Light as a probe of molecular structure
1. light is absorbed → excitation of molecule
2. de-excitation of molecule → light is emitted
• visible/UV: excitation of valence electrons
• infrared (IR):excitation of vibrations
• microwave/IR:excitation of rotations
APPLICATIONS
Raman Spectroscopy is a method of determining modes of molecular motions, especially
motions, especially vibrations. It is predominantly applicable to the qualitative and quantitative
analyses of covalently bonded molecules. Various applications are as follows
MICROWAVE INRAREDVISIBLE & ULTRAVIOLET

3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 83-89 © IAEME
85
HEADING TOWARDS SPECTROSCOPY
THERE ARE TWO TYPES OF SPECTROSCOPY AS FOLLOWS
Characteristic
regions for
different groups
as in IR
GOOD FOR
AQUEOUS
BASED
SAMPLES
Raman databases
available
IDENTIFICATIO
N OF PHASES
Useful for a
variety of
samples, organic,
inorganic &
biological
MOLECULAR
AND
CRYSTALINE
SYMMETRIES
MEASUREMEN
T OF STRESS
Identification of
crystalline
polymorphs
TYPES OF
SPECTROSCOPY
INFRARED
SPECTROSCOPY
RAMAN
SPECTROSCOPY

4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 83-89 © IAEME
86
1. Aspectrum is a graph of light intensity as a function of light frequency
2. From molecular structure, the compound can be identified
STARTING WITH IR SPECTROGRAPHY
RAMAN SPECTROGRAPHY
TO BE NOTED
1. Spectra shows vibrational frequency in wavenumbers (cm-1)
2. Peaks are used to identify chemical "groups", i.e. types of bonds
3. Examples of characteristics group stretching frequencies
Peaks in the spectrum give information about
molecular structure
IR SPECTROGRAPHY ABSORPTION
RAMAN SPECTROGRAPHY SCATTERING

5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 83-89 © IAEME
87
O-H 3600 cm-1
N-H 3400 cm-1
C-H 3000 cm-1
C-O/C-N/C-C 1100-1200 cm-1
C-C 1200 cm-1
aromatic C-C 1450-1600 cm-1
C=C 1650 cm-1
C≡C 2200 cm-1
1. Raman based on inelastic scattering of a monochromatic excitation source as
• Routine energy range: 200 - 4000 cm–1
• The Raman effect comprises a very small fraction, about 1 in 10^7 of the incident photons
Great for many real-world samples
- Minimal sample preparation (gas, liquid, solid)
- Compatible with wet samples and normal ambient
- Sample fluorescence is problematic
Raman Spectrum
A Raman spectrum is a plot of the intensity of Raman scattered radiation as a function of its
frequency difference from the incident radiation (usually in units of wavenumbers, cm-1). This
difference is called the Raman shift.
At the very most, the intensities of Raman lines are 0.001 % of the intensity of the source; as
a consequence, their detection and measurement are somewhat more difficult than are infrared
spectra
SELECTION RULES FOR IR
SPECTROSCOPY
SELECTION RULES DICTATE
WHICH MOLECULAR
VIBRATIONS ARE PROVIDED
SOME VIBRATIONS ARE
MADE OF BOTH IR AND
RAMAN EFFECT

6. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 83-89 © IAEME
88
1. The intensity or power of a normal Raman peak depends in a complex way upon the
polarizability of the molecule, the intensity of the source, and the concentration of the active
group.
2. The power of Raman emission increases with the fourth power of the frequency of the source.
3. Raman intensities are usually directly proportional to the concentration of the active species.
STOKES AND ANTISTOKES
I
N
T
E
N
S
I
T
Y
Raman Spectrum of CCl4
RAYLEIGH
I
N
T
E
N
S
I
T
Y
Raman Spectrum of CCl4(488.0 NM EXCITATION)
RAMAN SHIFT

7. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 83-89 © IAEME
89
Advantages of Raman
1. Selection rules allow for some vibrations (normally symmetric) to be seen only by Raman
spectroscopy.
2. Measurements of depolarization ratios yield information about molecular symmetry.
3. Water is a weak Raman scatterer, allowing for the use of aqueous solutions. Can also sample
through glass container walls.
CONCLUSION
1. The region 4000 cm-1 to 50 cm-1 can be covered in a single scan without changing gratings,
splitters,detectors, etc.
2. Only a small sample area is needed (laser spot)
3. Application of Raman Effect - Geology, Material Science, Petrochemistry, polymers,
Pharmaceutical Industry, NuclearScience, Forensic Science.
REFERENCES
1. Raman: theory and Raman: theory and instrumentation Kit Umbach Dept. of MS&E Dept. of
MS&E CCMR, NBTC facilities.
2. C.V. Raman and K.S. Krishnan, Indian J. Phys. 2, 387 (1928)
3. P.Straughan and S. Walker, Spectroscopy(Chapman and Hill, London, 1962), Vol.2, 198,
pg 225-258
4. S. Walker and H. Straw, Spectroscopy(Chapman and Hill, London, 1962) Vol. 2, p. 176.
5. A. Anderson, ed., The Raman Effect(Marcel Dekker, New York, 1971).
As you can see, the Stokes peaks correspond
to lower photon frequencies and lower
energies. The anti-Stokes side is symmetric
but corresponds to higher frequencies and
energies. The Stokes lines are stronger
because the population of molecules at ν=0
is much larger than at ν =1 by the Maxwell-
Boltzmann distribution law.