# Lifetime an atom can spend in an excited state

1. Nov 6, 2007

### randa177

Can you please give me a hint to start this problem?

The Einstein Aij coefficients are related to the lifetime an atom can spend in an excited state i before going to state j. Using Heisenberg’s Uncertainty Principle, show that large values of Aij lead to line profiles with large values of (lamda)

Thanks

2. Nov 6, 2007

### malawi_glenn

Heisenberg uncertanty principle: $$\Delta E \cdot \Delta t \sim \hbar$$

Let delta-t be the lifetime of the state. How is E related to lambda?

Last edited: Nov 6, 2007
3. Nov 6, 2007

### randa177

Oh, thanks a lot! That is very easy now!!
Thanks
Randa