Week 5 (17)

Question 1

When calculating the partition function, why is it okay to neglect multiple occupancy levels (i.e any atoms which have the same quantum numbers)?

Answer 1

This is okay as long as the possible states is much larger than the number of atoms

Question 2

What are fermions and bosons?

Answer 2

A fermion is a particle with half-integer spin, e.g electron, proton, C13 atom.

A Boson is a particle with integer spin, e.g Photon, He4 atom.

Question 3

What is the Pauli exclusion principle?

Answer 3

No two electrons in an atom can be in the same state or configuration at the same time (from antisymmetric wavefunction wrt particle exchange)

Question 4

For a Fermion system, how was the wave function related to particle exchange?

Answer 4

It is antisymmetric:

ψ(a,b) = -ψ(b,a)

Question 5

For a Boson system, how was the wave function related to particle exchange?

Answer 5

It is symmetric:
ψ(a,b) = ψ(b,a)

i.e the Pauli exclusion principle doesn’t apply.