M.Sc. DEGREE EXAMINATION, NOVEMBER 2017
Third Semester
Physics
MOLECULAR SPECTROSCOPY
(CBCS 2016 onwards)
Time 3 Hours Maximum 75 Marks
Part A (10 x 2 20)
Answer all questions.
1. Sketch the molecular orbital formation in ethylene.
2. Write down significance of exchange integral.
3. Define stark effect.
4. What is the change in the rotational constant B when
hydrogen is replaced by deuterium in the hydrogen
molecule?
5. What are hot bands? Why are they called so?
6. Which selection rule is used in intraved spectroscopy?
7. What is the requirement for a vibration to be Raman
active?
8. What is Raman effect?
9. Why gratings are not used in Raman spectrographs?
10. What is dipolar interaction?
Sub. Code
521301
RW-934
2
Wk 10
Part B x 5 25)
Answer all questions choosing either or
All questions carry equal marks.
11. Compare the MO wave function of hydrogen
molecule with that of the valence bond theory.
Or
Explain the SP hypridization.
12. Outline the importance of the study of quadrupole
hyperfine interaction in microwave spectra.
Or
Explain the rotational Raman spectra for linear
molecules.
13. State and explain Franck- Condon principle.
Or
Explain the fortrat parabolae.
14. Give an explanation on classical treatment of
Raman effect.
Or
Give an explanation on two photon absorption.
15. Describe the principle of ESR.
Or
Describe recoilless emission and absorption of
gamma rays.
RW-934
3
Wk 10
Part C x 10 30)
Answer any three questions.
16. Outline the Heitler-London wave functions for hydrogen
molecule. What are singlet and triplet states of hydrogen?
17. Explain the structure determination using IR and Raman
for XY2 ,XY3 and XY4 type of molecules.
18. Explain the vibrational spectra of diatomic and
polyatomic molecules.
19. Explain the stimulated Raman scattering.
20. Distinguish between spin lattice and spin-spin
relaxations.
Explain chemical shift with examples.
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