# Frequency of light calculated from wavefunctions

1. May 9, 2009

### granpa

if you have a wavefunction for an electron in one orbital and another wavefunction for the same electron in another orbital and assuming that the electron transitions from the one to the other orbital how would you derive the frequency of the emitted light from the wavefunctions themselves. (without just calculating the total energy released)

does the wavefunction have a frequency?

2. May 9, 2009

### ZapperZ

Staff Emeritus
This is a very ODD request.

You already know that one needs to find the energy eigenvalue to calculate such a thing. Yet, you want to find this another way and use the "wavefunction". That's like asking that you know a wrench can be used to tighten a bolt, but can we eat it as a cake?

The wavefunction is only meaningful in the sense that it can produce "observables" that have physical meanings. It is these observables that give you the physical quantities associated with various parameters that we know of. That is why the nature of these Hermitian operators (the observables) are as important as the wavefunction themselves.

Zz.

3. May 9, 2009

### malawi_glenn

the frequency of the emitted light IS related to the energy in the transition, the relation is just E = hbar * omega, so the energy eigenvalues of w.f's is the same as the freq. eigenvalue.

to first order approximation in explanation details, just take the energy eigenvalue of initial state w.f and the energy eigenvalue of the final state and subtract. But not all transitions are possible, but must obey certain selection rules /symmetries.

4. May 9, 2009

### granpa

Last edited by a moderator: May 4, 2017