CONCEPTS OF ELECTRONIC STATES AND TYPE OF FLUORESCENCE

CONCEPTS OF ELECTRONIC STATES AND TYPE OF FLUORESCENCE

COMCEPTS OF ELECTRONIC STATES 

1. Ground state :-  It is state of electron in which lowest energy states and highest stable.

2. Excited state :- It is state of electron in which highest energy states and lowest stable.

3. Singlet ground state :- It is the ground state consisting of paired electron in an orbit or suborbital with opposite spin.

4. Singlet excited state :- It is the excited state consisting of unpaired electron in orbital with opposite spin.

5. Triplet spin :- It is the state consisting of unpaired electron with same spin.

Electronic transition & Effect that produced 

  1. π→π∗ in this transition only absorption in radiation but not seen fluroscence
  2. π→π∗ (singlet transition) in this transition fluroscence are seen
  3. π→π∗ ( triplet transition) in this transition phosphorescence are seen.

Luminescence is the phenomenon of emission of light radiation substance when excitation occur in any form.

FLUORESCENCE + PHOSPHORESCENCE = luminescence

Type of fluorescence

1. Based upon the wave length of the emitted radiation when compared to absorbed radiation.

A. Stoke’s fluorescence :- the wavelength of emitted radiation longer than absorbed radiation.

B. Anti stoke fluorescence :- The wavelength of emitted radiation is shorter than the absorbed radiation.

C. Resonance fluorescence :- When the wavelength of emitted radiation is equal to the absorbed radiation. Eg. Mercury vapour.

MCQ

1. Which state electron possessed highest stable ?

A. Ground state

B. Triplet state

C. Singlet excited state

D. All of the above

Ans. A

2. Which state electron is less stable ?

A. Ground state

B. Excited state

C. Singlet excited state

D. None of this

Ans. B

3. Which state electron are in pair but opposite spin ?

A. Singlet ground state

B. Singlet excited state

C. A and B

D. None of this

Ans. A

4. π→π∗ electronic transition occur

A. Only absorption of radiation

B. Emissions of radiation

C. A and B

D. None of this

Ans.A

5. In which Excited state consisting of unpaired electron in orbital with opposite spin ?

A. Ground state

B. Excited state

C. Singlet excited state

D. All of the

Ans.c

6. flourescence + phosphorescence =

A. Photo-luminescence

B. Electro-chemiluminescence

C. Chemi-luminescence

D. All of the above

Ans. A

7. Phosphorescence when occur

A. Triplet transition

B. Singlet transition

C. Fluroscence

D. All of the above

Ans.A

8.The wavelength of emitted radiation is shorter than the absorbed radiation. This statement is correct for which type of Fluorescence

A. Stoke Fluorescence
B. Anti stoke Fluorescence
C. Resonance Fluorescence
D. All of the above

Ans. B

9. Which type of fluroscence the wavelength of the emitted radiation equal to the absorbed radiation ?

A. Stoke flourescence
B. Anti stoke flourescence
C. Resonance flourescence
D. All of the above

Ans. C

Reference take text book of pharmaceutical analysis of the third edition of the Dr. S. Ravi sankar

Page no. 3.4- 3.5

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