# Homework Help: Unidentified transition rate

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1. Dec 12, 2017

### yeshuamo

1. The problem statement, all variables and given/known data
I am identifying equations on the final exam equation sheet for my quantum II class. I've identified them all except this one, what I am guessing is a transition rate for some kind of emission or absorption of radiation case. Please help me identify the physical situation that this expression describes.

2. Relevant equations
This is the unidentified equation:
$$R_{i->f}=\frac{\pi}{2\hbar^2}\Big|\Big<\psi_f^o\Big|V\Big|\psi_f^o\Big>\Big|^2\delta(\omega_{fi}-\omega)$$

$$R\equiv\frac{dP}{dt}$$
, where P is the transition probability.

$$\omega_{fi} = \frac{E_f^o-E_i^o}{\hbar}$$
is the Bohr frequency for transition.

3. The attempt at a solution
I would integrate the transition rate over time to find the transition probability, but I don't think $\omega$ depends on time.

How do I identify the physical situations that this transition rate describes?

2. Dec 18, 2017

### Staff: Mentor

That's pretty much Fermi's Golden Rule, provided one of the $\psi_f^0$ is actually $\psi_i^0$.