Polyatomic Vibrations

Question 1

Number of vibrations for linear molecules

Answer 1

3N-5

Question 2

Number of vibrations for non-linear molecules

Answer 2

3N-6

Question 3

Internal rotation

Answer 3

Rotation of one part of the molecule with respect to the rest of it

Question 4

Where are local modes used

Answer 4

Spectroscopic assignments

Question 5

Normal mode

Answer 5

All nuclei undergo simple harmonic motion with same frequency and in phase but different amplitudes

Question 6

What happens to centre of mass in a vibration

Answer 6

Stays fixed

Question 7

Bending modes are

Answer 7

Degenerate