I How to choose the way an excited electron loses energy?

[GuillemVS]

TL;DR Summary

I want to know if it's possible to choose the way energy will be converted, when an electron is excited.

When electrons get excited they are unstable, therefore they want to go back to ground state. One way they do so is by creating photons (e.g. mirrors), but I've also read that they can create electricity (another electron?). Photoelectric is how it's called, right? If so, how can we choose wether if the electron is going to create a photon or another form of energy (e.g. electricity).

Thank you in advance.

 

[ZapperZ]

Summary: I want to know if it's possible to choose the way energy will be converted, when an electron is excited.

When electrons get excited they are unstable, therefore they want to go back to ground state. One way they do so is by creating photons (e.g. mirrors), but I've also read that they can create electricity (another electron?). Photoelectric is how it's called, right? If so, how can we choose wether if the electron is going to create a photon or another form of energy (e.g. electricity).

Thank you in advance.

You don't choose. Nature does that on her own.

If an excitation can lead to many different channels of decay, then you do not know which one it will choose. Now, depending on the situation, there may be one or more channel that is more favorable than others.

For example, if you excite an electron in the conduction band with, say, 20 eV photons, then there is an overwhelming probability that it will be emitted from the bulk material (photoelectric effect), rather than rattling around the solid and then decaying back to its original state inside the metal (generating heat). However, it doesn't mean that every single excitation will produce 100% of the time the emission of electrons.

This is why, when you learn quantum mechanics, you get to see all the various probabilities of the different states that a system can take. You do not have the ability to make 100% accurate prediction on a single event. You only have the ability to make a statistical prediction over the course of many events.

Zz.

 

[GuillemVS]

You don't choose. Nature does that on her own.

If an excitation can lead to many different channels of decay, then you do not know which one it will choose. Now, depending on the situation, there may be one or more channel that is more favorable than others.

For example, if you excite an electron in the conduction band with, say, 20 eV photons, then there is an overwhelming probability that it will be emitted from the bulk material (photoelectric effect), rather than rattling around the solid and then decaying back to its original state inside the metal (generating heat). However, it doesn't mean that every single excitation will produce 100% of the time the emission of electrons.

This is why, when you learn quantum mechanics, you get to see all the various probabilities of the different states that a system can take. You do not have the ability to make 100% accurate prediction on a single event. You only have the ability to make a statistical prediction over the course of many events.

Zz.

Then, antennas may fail because of this?
While receiving the information?

 

[ZapperZ]

Then, antennas may fail because of this?
While receiving the information?

No, because an antenna does not involve just ONE electron or transmit just ONE photon. The world that you are aware of is composed of a gazillion events per nanosecond. You are experiencing the statistical average of these numerous events.

Zz.

 

[GuillemVS]

No, because an antenna does not involve just ONE electron or transmit just ONE photon. The world that you are aware of is composed of a gazillion events per nanosecond. You are experiencing the statistical average of these numerous events.

Zz.

Oh, of course. Thanks for the reply ^^

 

[Nugatory]

Then, antennas may fail because of this?
While receiving the information?

With an antenna we are working with such an enormous number of photons and electrons that the individual quantum behavior of each one is irrelevant and the overall statistical behavior is all we see. That overall behavior is classical electromagnetism, so that's what we use in these problems.

There is an (almost unimaginably small) probability that an antenna will do something weird because a substantial fraction of the $10^{25}$ or more electrons in the antenna all do a low-probability thing at the same time... but it nevers happens. It's similar to how the ideal gas laws work: random motion of the gas molecules could cause the a pocket of vacuum to appear in one corner of a vessel, but it never happens.