Degrees of Freedom

Question 1

Types of motion

Answer 1

Translational, rotational and vibrational

Question 2

Translational motion

Answer 2

Movement of the centre of mass

Question 3

Rotational motion

Answer 3

Molecule turning around an axis

Question 4

Vibrational motion

Answer 4

Bonds stretching and bending causing the molecule to vibrate

Question 5

Linear molecule degrees of freedom with N atoms

Answer 5

3N,
For vibrational it has 3N-5 degrees of freedom as it cannot rotate around the axis of the molecule itself

Question 6

Non-linear molecule degrees of freedom with N atoms

Answer 6

3N
For vibrational it has 3N-6 degrees of freedom

Question 7

Linear molecule (CO2) vibrations

Answer 7

Symmetric (pulled apart bonds)
Anti-symmetric (one bond pushed one pulled)
Bending*2 (middle is pulled away from the sides for two axis’)