Ground state

  • Thread starter MathewsMD
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  • #1
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Main Question or Discussion Point

Just curious: if an electron absorbs a photon of energy, it is in an excited state. The electron may go to a lower energy state (but NOT the ground state). Can a photon (of higher wavelength than absorbed) be emitted still?

I don't quite see the importance of the electron having to go to the ground state in this case...
 

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  • #2
Drakkith
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Do you mean a longer wavelength, or a higher frequency? A "higher wavelength" doesn't make sense.

In any case, an electron can exist above the ground state, absorb a photon, and then fall to a lower state than what it was occupying emitting a photon of higher frequency than what it absorbed in the process.
 
  • #3
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Do you mean a longer wavelength, or a higher frequency? A "higher wavelength" doesn't make sense.

In any case, an electron can exist above the ground state, absorb a photon, and then fall to a lower state than what it was occupying emitting a photon of higher frequency than what it absorbed in the process.
Isn't a higher wavelength proportional to lower energy? How would it emit a higher energy photon (i.e. higher frequency) than what it absorbed?

So to confirm, a photon can still be emitted despite the electron not decaying to its ground state, just any state lower than its excited state, correct?
 
  • #4
ZapperZ
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A photon can be emitted if the system goes from a higher energy state to a lower energy state (not necessarily the ground state), and if it abides by the selection rule.

Example: the Balmer lines in H atom.

Zz.
 
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  • #5
Drakkith
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Isn't a higher wavelength proportional to lower energy? How would it emit a higher energy photon (i.e. higher frequency) than what it absorbed?
The extra energy required to emit a photon of higher frequency than the electron absorbs comes from the extra energy it already had by being in a state above the ground state.

So to confirm, a photon can still be emitted despite the electron not decaying to its ground state, just any state lower than its excited state, correct?
Absolutely.
 

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