Do Excited Molecules Emit the Same Frequency They Absorb?

[caybo]

1) When you excite amolecue and it releases photons off a given frequency, is that frequency the the very frequency which would best excite an identical molecue?

2) or are the release frequency(ies) and absorption frequency(ies) different?

3) If you excite a hydrogen atom with a certain frequency and it emits it's photons, will a different frequency make it it release a different freqency of photon back at us?

 

[Zizy]

Yes, No, Depends.

1 and 2) Electrons in atoms (or molecules, or bonds in molecules etc...) have discrete energy levels. If an electron jumps from one state to another it emits a photon with the same energy that is between those states. Absorbtion is mostly the same but in the opposite direction.
3) Depends on energy difference - if you put enough energy in the atom, emitted photon might have more energy. For smaller energy differences (you excite the atom with both frequencies to the same state), there is no difference in released photon.

 

[astrokreng]

1) The frequency at which a molecule releases photons upon excitation depends on its energy levels and the specific transitions between them. This frequency may or may not be the same as the one that would best excite an identical molecule. It is possible that different molecules may have different optimal excitation frequencies, depending on their molecular structure and energy levels.

2) The release and absorption frequencies of a molecule can be different. This is because the absorption of light by a molecule involves the promotion of electrons from lower energy levels to higher energy levels, while the emission of light involves the relaxation of these excited electrons back to their lower energy levels. These energy levels may not be the same, resulting in different frequencies for absorption and emission.

3) Yes, a different excitation frequency can result in the emission of a different frequency of photon from a hydrogen atom. This is because the energy levels and transitions of the hydrogen atom are specific to its atomic structure and can be affected by different excitation frequencies. Therefore, changing the excitation frequency can lead to different energy level transitions and subsequently, different emission frequencies.