Molecular Vibrations

Question 1

What is a good way to model vibrations of molecules?

Answer 1

With a Hooke’s -law style set of masses and springs.

Question 2

What is the equation for the potential at a point r between the masses connected by spring?

Answer 2

V(r) = 1/2 k’(r-r0)^2, where 20 is the distance between the masses

Question 3

What is the energy difference between quantum states equal to?

Answer 3

ћω, ω = sqrt(k’/μ)

Question 4

What does μ represent in the equation for ω? What does k’ represent?

Answer 4

The reduced mass: μ = m1m2/(m1+m2). k’ represents the strength of the chemical bond.

Question 5

What do molecules have to do to absorb or emit photons?

Answer 5

Change their vibrational state.