LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 15

SIXTH SEMESTER – APRIL 2006

                                                     CH 6600 – MOLECULAR DYNAMICS

(Also equivalent to CHE 600)

 

 

Date & Time : 19-04-2006/FORENOON     Dept. No.                                                       Max. : 100 Marks

 

 

                                                            PART – A                            

            Answer ALL questions.                                            (10 ´ 2 = 20 marks)

 

1. State the de Broglie relation. Explain the condition under which it is applicable.
2. Normalise e^ax in the interaval (0,1).
3. What are the possible values for angular momentum according to Bohr’s postulate?
4. Give the expressions for wave function and energy for the third p-energy level of 1,3-
5. Evaluate ln N! when N = 10³⁰ using Stirling’s formula.
6. Calculate the number of ways of distributing four particles among five energy levels if the particles are electrons.
7. Write Boltzmann equation connecting entropy and thermodynamic probability.
8. What is intersystem crossing?
9. Define quantum yield of a photochemical reaction.
10. Mention any four relaxation methods used in the kinetic study of fast reactions.

 

PART – B                 

       Answer any EIGHT questions.                                     (8 ´ 5 = 40 marks)

 

11. Determine the kinetic energy of the electrons emitted by a light of 100 nm if the threshold frequency of the metal is 9.0 ´ 10¹⁴
12. Calculate the ionization energy per mole of H atom.
13. Derive the expression for Hamiltonian operator in cartesian coordinates.
14. Examine whether “A sin ax” is Eigen function for the second order differential operator. If so, state the Eigen value.
15. Calculate the wave length of transition for a conjugate olefin containing 3 double bonds.
16. Explain how partition functions can be separated.
17. Calculate the ratio of translational partition function of D₂(g) to H₂(g)  at the same temperature and volume.
18. Write Sackur-Tetrode equation and mention the terms involved.
19. Derive the relation connecting internal energy(E) and molecular partition function(Q).
20. Explain the principle of flash photolysis.
21. Explain the factors affecting phosphorescence emission.
22. Explain photosensitisation with two examples.

 

PART – C

       Answer any FOUR questions.                                      (4 ´ 10 = 40 marks)

 

23. Obtain an expression for the radius of “H” atom on the basis of the Bohr’s model of atom.
24. Obtain the expressions for the energy and wave function of a free particle in a one dimensional box.
25. State the postulates of Maxwell-Boltzmann distribution law and hence derive an expression for most probable distribution.
26. Explain any two of the following
    (a) Fluorescence and structure

• Kinetics of H₂-Br₂ (photochemical) reaction.
• Chemical actinometer.

27. Draw Jablonski diagram and explain in detail.
28. Derive the following

(a)  E = RT²

(b)  E_translation =

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 17

B.Sc. DEGREE EXAMINATION – CHEMISTRY

SIXTH SEMESTER – APRIL 2007

CH 6600 – MOLECULAR DYNAMICS

 

 

 

Date & Time : 16.04.2007/9.00-12.00      Dept. No.                                                      Max. : 100 Marks

 

 

 

 

Part A

Answer ALL questions.                                                                        (10 ´ 2 = 20 marks)

1. Define (i) particle (ii) wave
2. Bring out the difference between photoelectric effect and Zeemann effect.
3. Determine the Eigen value for “Ae^-ax for the operator (d/dx²)”^.
4. What is the condition for φ₁ and φ₂ to be orthogonal functions in the interval [a,b]
5. Explain the difference between thermodynamic probability and mathematical probability?
6. Explain phosphorescence in terms of spin multiplicity
7. Define quantum yield of a photochemical reaction.
8. Define steady state approximation. What is its advantage?
9. What is residual entropy? Give an example.
10. Calculate the number of ways of distributing 4 fermions among 8 energy levels.

 

 

Part B

Answer any EIGHT questions.                                                            (8 ´ 5 = 40 marks)

 

 

11. Explain the energy distribution in black body
12. An electromagnetic radiation of wave length 200Å is incident on a metal surface of threshold frequency 6.53×10¹⁴ Hz .Calculate the velocity of the electrons emitted.
13. Calculate the wave length of the lowest energy of the Balmer
14. Calculate the ground state energy of a π-electron in 1, 3-butadiene. (The C=C & C-C bond distances are 1.33 and 1.54 Å, respectively).
15. Explain the concept of separation of partition
16. Derive an expression for the translational partition function.
17. Draw Jablonski diagram and indicate the difference between fluorescence and phosphorescence. Discuss also their difference with regard to transition (pathways), duration, and change in spin multiplicity.
18. Mention the various factors affecting fluorescence and phosphorescence and discuss any two factors in detail giving one example each.
19. Discuss the principle and working of Uranyl Oxalate Actinometer.
20. Discuss the differences in the kinetics of the two photochemical reactions of H₂ with Cl₂ and H₂ with Br₂.
21. Write Sackur-Tetrode equation and define the terms involved. Also explain how the translational entropy of a gas varies with (a) temperature (b) pressure (3+2)
22. (a) Differentiate fermions and bosons statistically.

(b) Calculate the molar residual entropy of a crystal in which the molecules can adopt

24 orientations of equal energy at 0K.                                                                 (3+2)

 

 

 

Part C

              Answer any FOUR questions.                                                            (4 ´ 10 = 40 marks)

 

23. Discuss, with a suitable diagram, the different types of lines produced in the emission spectrum of atomic hydrogen.
24. Derive an expression for the energy of a particle in a one dimensional box on the basis of quantum mechanics.
25. Derive an expression for the most probable distribution on the basis of classical statistics.
26. Discuss the mechanism and kinetics of the photochemical reaction between H₂ and Br₂.
27. Mention the different types of quenching and derive Stern-Volmer equation for bimolecular quenching.                                                                                                             (3+7)
28. Mention any four relaxation techniques and derive an expression for relaxation time for a reaction involving equilibrium A = B (both I order) using temperature-jump method. (2+8)

 

* * * * *

 

SOME USEFUL CONSTANTS:

1. Planck’s constant = 6.625 x 10^-34 Js
2. Boltzmann constant = 1.38 x 10^-23 JK^-1
3. Velocity of light = 3 x 10⁸ ms^-1
4. Avogadro number = 6.023 x 10²³
5. Rydberg constant = 1.097 x 10⁷ m^-1

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    LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

WD 19

SIXTH SEMESTER – April 2009

CH 6606 / 6600 – MOLECULAR DYNAMICS

 

 

 

Date & Time: 18/04/2009 / 9:00 – 12:00     Dept. No.                                                       Max. : 100 Marks

 

 

PART – A

 

Answer ALL questions.                                  (10 x 2 = 20 marks)

 

1. Define the term orbit and orbitals.

 

2. State Pauli’s exclusion principle.

 

3. Define the term degeneracy of an energy level.

 

4. What is Quantum Yield?

 

5. Give the significance of φ².

 

6. Find the value of ln N_A!, ( Where  N_A   is Avagadro’s number )using Stirlings

approximation.

 

7. State the Stark-Einistien’s law.

 

8. Define Chemiluminescence.

 

9. What are thermal reactions? Give an example.

 

10. Mention any two methods of studying fast reactions.

 

PART – B

 

Answer any EIGHT questions.                                               (8 x 5 = 40 marks)

 

11. How is photoelectric effect explained by quantum theory.

 

12. Calculate the radius of the electron in the first orbit of hydrogen atom.

 

13. Derive the expression for the energy of an electron in the n^th shell of hydrogen.

 

14. State the postulates of quantum mechanics and explain any one of them.

 

15. Define the Laplacian operator and Hamiltonian operator.

 

16. Explain Sackur-Tetrode equation and mention the terms involved.
17. A system of N particles has among others, two energy levels with g₁ = 2,

g₂ = 3, E₁ = 41.84 kJmol^-1  and  E₂ = 58.58 kJmol^-1.   Calculate the ratio of the number of particles in the two energy states at 1000K.

 

18. Derive the relation between partition function and energy.

 

19. Explain Photo sensitisation.

 

20. Explain the primary and secondary processes in a photochemical reaction.

 

21. Describe flash photolysis.

 

22. Explain the kinetics of photochemical reaction between  H₂  and  Br₂.

 

PART – C

Answer ANY FOUR questions.                                 (4 x 10 = 40 marks)

 

23. Explain (i) Black body radiation (ii) Separation of partition function.

 

24. Derive the expression of Eigen value ‘E’ and Eigen function  ‘ψ ‘ for a particle

in one dimensional box.

 

25. (i) Derive an expression for translation partition function.

(ii)        Calculate the translational partition function for benzene in a volume of

1 m³ at 25^oC.

 

26. Derive the Maxwell – Boltzmann distribution law.

 

27. Explain any tow of the following

(i)         Radiationless transition.

(ii)        Phosphorescence

• Actinometers
• Zeemann effect

 

28. (i) Derive the Stern-Volmer equation.

(ii)        Explain Jablanski diagram.

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

SIXTH SEMESTER – APRIL 2011

CH 6606/CH 6600 – MOLECULAR DYNAMICS

 

 

 

Date : 05-04-2011              Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

 

PART – A

Answer ALL questions.                                                                              (10 x 2 = 20 marks)

 

1. Define the terms orbit and orbitals.
2. Calculate the energy of the photon associated with light of wavelength 4000 A^o.
3. Define the term degeneracy of an energy level.
4. What are operators? Give an example.
5. Find the value of ln100!
6. Define thermodynamic probability.
7. What is internal conversion?
8. What is quantum yield?
9. What are thermal reactions? Give an example.
10. What is Photosensitization?

 

PART – B

Answer any EIGHT questions.                                                                    (8 x 5 = 40 marks)

 

11. How is photoelectric effect explained by quantum theory.
12. Explain the energy distribution in Black Body radiation.
13. Explain Zeeman effect.
14. State the postulates of quantum mechanics.
15. Derive on Schrodinger wave equation.
16. Explain Sackur-Tetrode equation.
17. Explain the relation between partition function and energy.
18. Explain the mechanism of photosynthesis.
19. Explain the primary and secondary processes in a photochemical reaction.
20. When irradiated with light of 5000 A^o wavelength, 1 x 10^-4 mole of a substance is

decomposed.  How many photons are absorbed during the reaction if its quantum

efficiency is 10.00 (Avogadro number N = 6.02 x 10²³)

21. Explain Flash photolysis.
22. Discuss the kinetics of photochemical reaction between H₂ and Cl₂.

 

 

 

PART – C

Answer any  FOUR  questions.                                                                 (4 x 10 = 40 marks)

 

23. (i) Derive an expression for energy of an electron using Bohr’s theory.

(ii) State Pauli’s exclusion principle and explain.

 

24. (i) What is the minimum energy that photons must possess in order to produce

photoelectric effect with platinum metal?  The threshold frequency for platinum

is  1.3 x 10¹⁵ sec^-1.

 

(ii)   Derive the expressions for eigen value and eigen function for a particle in one

dimensional box.

 

25. Derive an expression for translation partition function. Mention its significance.                         (7+3)

 

26. Derive Maxwell-Boltzmann statistics. Give its application.                                                            (7+3)

 

27. Explain any two of the following:

(i)    Actinometers                                              (ii)    Phosphorescence

(iii)  Chemiluminescence                         (iv)   Radiationless  transition                             (5+5)

 

28. a) Derive Stern-Volmer equation.

 

1. b) Explain Jablonski diagram.                                                                                                         (5 +5)

 

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

SIXTH SEMESTER – APRIL 2012

CH 6606/CH 6600 – MOLECULAR DYNAMICS

 

 

 

Date : 16-04-2012              Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

 

PART – A

Answer ALL questions:                                                                                            (10 x 2 = 20 marks)

 

1. Define the terms orbit and orbitals.
2. Calculate the energy of the photon associated with light of wavelength 3200 A^o.
3. Define the term degeneracy of an energy level.
4. What are operators? Give an example.
5. What are microstates?
6. Define the term partition function.
7. Explain internal conversion.
8. What is quantum yield?
9. State the Grotthus-Draper’s law of photochemistry.
10. Define molar extinction coefficient.

 

PART – B

Answer any EIGHT questions.                                                                                (8 x 5 = 40 marks)

 

11. Explain the difference between classical mechanics and quantum mechanics.
12. Explain the energy distribution in Black Body radiation.
13. Explain Zeeman effect.
14. State the postulates of quantum mechanics.
15. Explain the significance of eigen functions.
16. Derive Sackur-Tetrode equation and explain the terms involved.
17. Discuss the most probable distribution of particles.
18. Explain the spin-orbit coupling.
19. Explain the primary and secondary processes in a photochemical reaction.
20. Radiation of wave length 2500 Ǻ was passed through a cell containing 10 ml of a

solution which was 0.05 molar in oxalic acid and 0.01 molar in uranyl sulphate.   After absorption of

80 Joules of radiation energy, the concentration of oxalic acid was reduced to 0.04 molar.   Calculate

the quantum yield for the photochemical decomposition of oxalic acid at the given wave length.

21. Explain the kinetics of fast reaction by relaxation techniques.
22. Discuss the kinetics of photochemical reaction between H₂ and Br₂.

PART – C

Answer any  FOUR  questions:                                                                 (4 x 10 = 40 marks)

 

23. (i) What are quantum numbers?  Give its significance.

(ii)  A photon of wave length 4000 Ǻ strikes a metal surface, the work function of the

metal being 2.13 eV.   Calculate the energy of the photon in eV.

 

24. (i) State Pauli’s exclusion principle and explain.

(ii)  Derive the expressions for eigen value and eigen function for a particle in one

dimensional box.

 

25. Explain the separation of partition functions and its significance.

 

26. Derive Maxwell-Boltzmann statistics.

 

27. Explain any two of the following:

(i)    Chemical Actinometers                           (ii)    Fluorescence

(iii)  Chemiluminescence                                 (iv)   Flash photolysis

 

28. Derive Stern-Volmer equation. Give its applications.

 

 

 

 

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