rasonance raman stecroscopy

1. guided By :-Dr. Rachna Dube
.
presented by:-varsha tidke
Resonance Raman
spectroscopy

2. RAMAN SPECTOSCOPY
Raman spectroscopy is based on scattering of
radiation (Raman scattering), which is a
phenomenon discovered in 1928 by physicist Sir C.
V. Raman.

3. RASONANCE RAMAN SPECTROSCOPY
 when the incident laser frequency is close in
energy to an electronic transition of a
compound or crystal under examination.The
frequency coincidence (or resonance) can lead
to greatly enhanced intensity of the Raman
scattering, which facilitates the study
of compounds present at low concentrations.[

6. The Raman intensity is directly proportional to (Ve-
V0) asV0 approach to the denominator is become
very small. Hence , this term (“resonance term”)
become so large that the intensity of the Raman
band at (Ve-V0) increase enormously
How intensity is enhanced?

7. Absorption spectra of compound contain
two chromophoric (A and B)

8. theory
 The theory of resonance Raman effect is
much complex .
 The polarizability theory fails under
resonance condition
 The selection rule appearance of overtone
 Only totally symmetric fundamental may
show the effect

9. Overtone band

10. Fundamental and overtone
band

11. Rss active or inactive

12. Technique
 The experimental setup for RSS is same as
that used for normal Raman spectroscopy.
 Gas lasers or tunable dye lasers are used for
excitation.
 The effect of over heating can be prevented
by spinning the sample rapidly

13. application
 enharmonic and harmonic frequency is accurately
determine .
 RSS is well suited for the study of free radical and
transient species.
 It represent a great simplification which is focus
directly on specific part of the molecule.
 It is used for studding biostructural problem and
complex biological material.
 Excitation profile of Raman show close relationship
b/w Raman and electronic spectroscopes.

14. Thankyou