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K8181
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Can someone please explain why an excited electron in an atom decays to the ground state, if energy eigenstates are stationary states.
Dr.Brain said:When you excite an electron via radiation or any wave carrying some threshold energy , the electron absorbs the energy. Initially electron is in an orbit with energy -E , so the electron has also got same energy -E , now when it gains some energy 'K' , its energy becomes -(E+K) which is less than the initial E because of the minus sign. As lower energy levels are more stable and have lesser energy , the electron excites itself from its initial state to a more stable state by gaining certain amount of needed energy from the radiation.
As the name implies, the 'ground state' is the basic state of an atom. Each type of atom has its own unique ground state. With respect to the last electron, all lower energy states are filled with other electrons. An excited electron will exist in upper energy states only briefly before dropping back to the ground state and emitting a characteristic photon. That's just the way it is.K8181 said:Can someone please explain why an excited electron in an atom decays to the ground state, if energy eigenstates are stationary states.
marlon said:It is not the electron that is excited but the atom to which the electron 'belongs'
SpaceTiger said:If there is only one electron in the atom, don't you think this point is largely semantic? There is some coupling between the electron and the nucleus, but its a very small effect. The wave function is basically that of an electron in a potential well.
marlon said:What i wanted to point out is the fact that these energy levels come from the fact that the electron interacts with the nucleus. You mentioned it yourself : an electron in a potential well.
SpaceTiger said:But by that definition, it would then be improper to say that a planet could be excited to a higher-energy orbit because, after all, the planet wouldn't be orbiting without the sun. You'd have to say, instead, that the solar system is excited to a different energy state. I have a feeling that dynamicists would look at you strange if you used this terminology.
It certainly is not. I am just presenting the QM description of an atom and how it is responsible for the specific electronic energy levels.I know our argument is largely semantic,
I often hear ISM physicists talk in terms of what happens to the "electron" in an atom, rather than always discussing in terms of the atom as a whole. This description is often more helpful for understanding what's going on inside of the atom, even if the language is somewhat imprecise.
marlon said:I really don't know why you bring in this analogy. Anyway it is totally wrong because the phenomena we are talking about (electrons in atoms) are totally different compared to celestial motions. I mean, let us not start mixing QM with classical mechanics. That is why this analogy is erroneous.
the energylevels are not inherent to the actual electrons but to the electron-nucleus interaction
It is fundamental that people understand how these electronic energy levels arise. You cannot deny the fact that a Fermi-gass has different behavior then electrons 'inside' atoms.
SpaceTiger said:We're discussing the distinguishability of the individual components of the system, not their behavior.
No it is not. You are referring to a classical system. If you would apply this system onto the electrons and the nucleus, you would not even have stable atoms. It is this way of thinking that gives rise to questions like 'why doesn't an electron crash into a nucleus and why doesn't it radiate ?' I have been answering such misconceptions ad nauseum...Thus, my analogy is appropriate, as this fact is also true of planets around the sun.
I don't see your point. An object will of course behave differently when put under different external restrictions.
That doesn't mean, however, that it's inappropriate to consider it as a separate entity.
marlon said:Yes we very much are...
Again, the electronic levels very much explain the actual electronic behavior. You cannot talk about these energy levels without explaining where they came from and why they exist. I challenge you to explain this without bringing in the atomic nucleus.
Besides this 'distinguishability' does not exist in QM.
No it is not. You are referring to a classical system. If you would apply this system onto the electrons and the nucleus, you would not even have stable atoms. It is this way of thinking that gives rise to questions like 'why doesn't an electron crash into a nucleus and why doesn't it radiate ?' I have been answering such misconceptions ad nauseum...
My point was that free electrons are NOT the same as electrons in an atom.
You cannot just talk about some electron and its 'possible' energy levels because in the end people will ask : where do these energy levels come from ?
SpaceTiger said:Again, I challenge you to explain the energy of Pluto without invoking the sun. This is beside the point.
How can you say that? The entire concept of the Pauli Exclusion Principle is based on the distinction between distinguishable and indistinguishable particles.
to the electron-nucleus interaction".
4) I gave an example of a system in which the components were considered separate, despite the above being true.
:) YES, it's better then not being able to answer the actual question isn't it ? Ofcourse if people want a full blown justification of this, then we both know there is only one option.And you simply answer, "the interaction of the electron with the nucleus".
marlon said:But this is very much the point. I asked you a specific question which you could not answer.
My point is that electrons in atoms exhibit their energy levels because of interactions with the nucleus, eg : L-S-coupling or Coulombic-interaction.
As a proof : a free electron has no such energy states. This is why i asked you about electrons in ayoms and free electrons.
You cannot distinguish between different electrons that make up any Fermi-gass...What is your point ? All electrons obey this very same Pauli principle, so how can it be used to distinguish between electrons.
But in the example that you gave, isn't there an interaction going on that determins how the bodies move and what energy they exhibit ? I think so...So i really don't see the justification for your analogy.
Again, what i said is that the energy levels of electrons in atoms are determined by their interaction with the actual nucleus. Why is this so hard to get ? It's quite elementary if you think about it...
marlon said:ps : what did i read about a photon decaying ?
marlon said:That is just what i wanted to clarify : the energylevels are not inherent to the actual electrons but to the electron-nucleus interaction.
regards
marlon
marlon said:Yes we very much are...
Again, the electronic levels very much explain the actual electronic behavior. You cannot talk about these energy levels without explaining where they came from and why they exist. I challenge you to explain this without bringing in the atomic nucleus.
marlon said:Besides this 'distinguishability' does not exist in QM.
marlon said:I have been answering such misconceptions ad nauseum...
SpaceTiger said:Again, I challenge you to explain the energy of Pluto without invoking the sun. This is beside the point.
marlon said:My point is that electrons in atoms exhibit their energy levels because of interactions with the nucleus, eg : L-S-coupling or Coulombic-interaction.
marlon said:Again, what i said is that the energy levels of electrons in atoms are determined by their interaction with the actual nucleus. Why is this so hard to get ? It's quite elementary if you think about it...
dextercioby said:What energy...?
dextercioby said:I hope u got the picture.I've said it 3 times already.
SpaceTiger said:Three times before he could respond. Why don't you say it a fourth time and maybe you'll look smarter? :grumpy:
dextercioby said:I think you just ruled out spin-spin interaction in the case of electrons (Fermi gas) and a great deal of the theory behind "magnetism"...
Daniel.
dextercioby said:Hyperfine structure due to electron spin-electron spin coupling...?
Excited electrons decay to the ground state because they are in an unstable, high-energy state and naturally seek to reach a more stable, lower-energy state. This process is known as relaxation or de-excitation.
An excited electron can decay to the ground state through various processes such as emitting a photon of light, transferring its energy to another particle, or undergoing a collision with another particle.
The rate of electron decay to the ground state can be affected by factors such as the energy difference between the excited and ground states, the presence of other particles that can interact with the electron, and the temperature of the system.
Yes, excited electrons can decay to states other than the ground state. This is known as a non-radiative decay, where the electron transfers its energy to another particle without emitting a photon. However, the ground state is the most common destination for excited electrons to decay to.
Understanding electron decay to the ground state is crucial in fields such as quantum mechanics, atomic and molecular physics, and material science. This knowledge helps us understand the behavior of atoms and molecules, as well as develop technologies such as lasers and semiconductors.