Jump to content

Why do electrons obey certain levels?


quanta

Recommended Posts

If the proton coloumb force is equal on all electrons and is what holds electrons in place..., what "tells" an electron to stay at such and such level and others at another?

 

And at these levels is it correct to assume that they are simple harmonic oscillators ie. "mass of on a spring" ? Like the Loretz oscilator model, rather than the bohr atomic model of orbitals? Actually I have been trying to combine the two, where only if electrons are not in a bond do they have an additional degree of freedom such as a classical orbit, but not quite a complete orbit, just a degree of freedom around the nucleus... where when electrons are shared they form a molecular bond and lose this freedom... right?

 

Another question related to the first, what is the force that shifts momentum back to the nucleus?.. going toward the peak of its amplitude... where in classical physics this could be gravity, obviously its not gravity is it? Can I assume that the force that attracts to nucleus, and the force that pushes from nucleus is not a force with equal rates of falloff? ie. one or the other is stronger at x distance but then with a greater distance that same force is less strong then the other, the reason why it oscilates...?? Because if not and the forces are mathmatically identical, then the electron would find equilibrim and be idle..??

Link to comment
Share on other sites

If the proton coloumb force is equal on all electrons and is what holds electrons in place...' date=' what "tells" an electron to stay at such and such level and others at another?

 

And at these levels is it correct to assume that they are simple harmonic oscillators ie. "mass of on a spring" ? Like the Loretz oscilator model, rather than the bohr atomic model of orbitals? Actually I have been trying to combine the two, where only if electrons are not in a bond do they have an additional degree of freedom such as a classical orbit, but not quite a complete orbit, just a degree of freedom around the nucleus... where when electrons are shared they form a molecular bond and lose this freedom... right?

 

Another question related to the first, what is the force that shifts momentum back to the nucleus?.. going toward the peak of its amplitude... where in classical physics this could be gravity, obviously its not gravity is it? Can I assume that the force that attracts to nucleus, and the force that pushes from nucleus is not a force with equal rates of falloff? ie. one or the other is stronger at x distance but then with a greater distance that same force is less strong then the other, the reason why it oscilates...?? Because if not and the forces are mathmatically identical, then the electron would find equilibrim and be idle..??[/quote']

 

The energy levels within the atomic system are quantized, so only certain energy levels are allowed. The electron remains bound because it has PE + KE < 0 . The Bohr model is physically wrong, as the orbits are not circular - atoms are not miniature solar systems. Modeling a system as a harmonic oscillator is an approximation that is often used, but is only valid where the potential actually looks like a harmonic oscillator, which isn't always the case. The force is electromagnetic.

Link to comment
Share on other sites

The energy levels within the atomic system are quantized, so only certain energy levels are allowed. The electron remains bound because it has PE + KE < 0 . The Bohr model is physically wrong, as the orbits are not circular - atoms are not miniature solar systems. Modeling a system as a harmonic oscillator is an approximation that is often used, but is only valid where the potential actually looks like a harmonic oscillator, which isn't always the case. The force is electromagnetic.

 

I guess I was going to edit my original post and get rid of some things.. but anyway Ill reply to this.

 

Right so, quantum leaps are like marks on a ruler. However Id be curious to know why there are only typically 6 levels and a few subshells, Should there not be a very fine structure?? Like exactly inversely proportional to the EM spectrum? ie. an electron emits a say 'visible light - green photon' and drops down to a level indicitative of exactly that much energy lost... Ok think of it like this, a valence electron has a "potential energy" (magnitude of "stored" photon energy) and wavefunction equivilent to an photon of say infrared, so its total potential energy is the maximum amount of energy it can lose to bring it to ground state, that being in this case if it emited an infrared photon.

But lets assume that it loses a very small amount of energy by emiting a radio wave, that would drop it to a level (NIF 300THz 1.24eV) - (ELF 30Hz 124feV) Result is it should still be in the infared range just slightly less energy. So my question is how does this fit into a model of only 6 possible levels? I mean it cant quantum leap between a 1s orbital and a 2s orbital by gaining or losing such a small energy photon. Quantum leaps are suppose to be fine structure ie. the smallest possible increment. but the model doesnt support it does it?? Ok thats my reply to your first sentence ;)

 

PE + KE < 0 I dont understand, why would either be considered such? And what does that necessarily have to do with how it is bonded?

 

Ive already said that the bohr model motion is only applicable in situations where no bond is present, and that regardless if its in a bond or not, it has an ocsillatory wavefunction. do you agree?

 

What force is electromagnetic? Are you trying to tell me that EM is the push force? Clearly the Proton coloumb force is the attractive force on electrons... I just want to know what the push force is that makes it a harmonic oscillator... And its definatly not EM so I dont even know in what context you even would mention EM. Unless you meant between electrons.. um Of course I meant between the nucleus and electrons. If I can try and answer my own question, it would seem that a bohr orbital motion is required to give explaination to a semi-classical centrifugal force, our mysterious push force. Of course in molecular bonds, the electron loses this bohr motion and just ocsilates inbetween the two coloumb sources... that part needs refining too because we need to explain why if it does not, find an equilibrim and lose its wavefunction, of course it may very well do so to a large degree. However then we run into the problem of differenciating it between a valence bond electron and a ground state electron based on its wavefunction alone. Sorry I'm rambling to myself here.

Link to comment
Share on other sites

I guess I was going to edit my original post and get rid of some things.. but anyway Ill reply to this.

 

Right so' date=' quantum leaps are like marks on a ruler. However Id be curious to know why there are only typically 6 levels and a few subshells, Should there not be a very fine structure?? Like exactly inversely proportional to the EM spectrum? ie. an electron emits a say 'visible light - green photon' and drops down to a level indicitative of exactly that much energy lost... Ok think of it like this, a valence electron has a "potential energy" (magnitude of "stored" photon energy) and wavefunction equivilent to an photon of say infrared, so its total potential energy is the maximum amount of energy it can lose to bring it to ground state, that being in this case if it emited an infrared photon.

But lets assume that it loses a very small amount of energy by emiting a radio wave, that would drop it to a level (NIF 300THz 1.24eV) - (ELF 30Hz 124feV) Result is it should still be in the infared range just slightly less energy. So my question is how does this fit into a model of only 6 possible levels? I mean it cant quantum leap between a 1s orbital and a 2s orbital by gaining or losing such a small energy photon. Quantum leaps are suppose to be fine structure ie. the smallest possible increment. but the model doesnt support it does it?? Ok thats my reply to your first sentence ;)[/quote']

 

 

Atomic systems have an infinite number of states. There are the principle states, and then there are states with different angular momenta and spin, with fine structure and hyperfine structure.

 

PE + KE < 0 I dont understand' date=' why would either be considered such? And what does that necessarily have to do with how it is bonded?[/quote']

 

For an attractive force, PE is negative. A bound system has PE + KE <0

An electron that is bound lacks the energy to escape, which is why is why it doesn't escape. This defecit of energy is the ionization energy for the "outermost" (energetically) electron - the energy needed to free the electron.

 

Ive already said that the bohr model motion is only applicable in situations where no bond is present' date=' and that regardless if its in a bond or not, it has an ocsillatory wavefunction. do you agree?

 

What force is electromagnetic? Are you trying to tell me that EM is the push force? Clearly the Proton coloumb force is the attractive force on electrons... I just want to know what the push force is that makes it a harmonic oscillator... And its definatly not EM so I dont even know in what context you even would mention EM. Unless you meant between electrons.. um Of course I meant between the nucleus and electrons. If I can try and answer my own question, it would seem that a bohr orbital motion is required to give explaination to a semi-classical centrifugal force, our mysterious push force. Of course in molecular bonds, the electron loses this bohr motion and just ocsilates inbetween the two coloumb sources... that part needs refining too because we need to explain why if it does not, find an equilibrim and lose its wavefunction, of course it may very well do so to a large degree. However then we run into the problem of differenciating it between a valence bond electron and a ground state electron based on its wavefunction alone. Sorry I'm rambling to myself here.[/quote']

 

The electromagnetic force on charges is attractive or repulsive, depending on the charge (electrostatic) or neither (magnetic - the force is perpendicular to the velocity). You need an attractive force to make a harmonic oscillator, which in this case would be the attractive electrostatic force.

Link to comment
Share on other sites

I need to know why it is bound at the distance it is bound... And why this distance is not finestructure specifically according to photon emmision and absorption Which IS finestructure so to speak. ie. EM spectrum is more or less finestructure is it not? Relativistic effects would make it so if nothing else.

 

Hyperfine structure, "splitting" are relativistic doppler effects in atomic spectral lines that arise from perturbations of PE and KE of photo-electrons wavefunctions due to magnetic moment dipole and quadrapole interactions between the nuclei and electrons imparted to each own respectively and as a whole. This kind of phenomenon is aside from the question at hand.

 

 

"For an attractive force, PE is negative. A bound system has PE + KE <0"

 

Your wrong. And i know about ionization energy. However there are possible more than one defintion of potential energy, a purely classical momentum limit and a quantum potential that being released as radiation. Where the former is a measure of the charge field strength and the later being a measure of electron mass to energy conversion potential; assuming that an electron can gain or lose mass/energy and thats how we describe change in "orbital distance" conditioned by radiation only, not by coloumb forces. And my question is again, where is the fine structure for orbital distances according to radiation?

 

"The electromagnetic force on charges is attractive or repulsive, depending on the charge (electrostatic) or neither (magnetic - the force is perpendicular to the velocity). You need an attractive force to make a harmonic oscillator, which in this case would be the attractive electrostatic force."

 

Ya and you Completely missed my point, which was what is the repulsive force that completes the second half of the waveform. And i already figured it out. so dont bother.

Link to comment
Share on other sites

I need to know why it is bound at the distance it is bound... And why this distance is not finestructure specifically according to photon emmision and absorption Which IS finestructure so to speak. ie. EM spectrum is more or less finestructure is it not? Relativistic effects would make it so if nothing else.

 

Hyperfine structure' date=' "splitting" are relativistic doppler effects in atomic spectral lines that arise from perturbations of PE and KE of photo-electrons wavefunctions due to magnetic moment dipole and quadrapole interactions between the nuclei and electrons imparted to each own respectively and as a whole. This kind of phenomenon is aside from the question at hand.[/quote']

 

 

"fine structure" has a specific meaning in atomic physics, which appears to be different than how you are using it. If these other phenomena are no relevant, then I don't have a handle on what you are meaning. The interaction you previously described (electron having a visible-light transition emitting a radio wave) does not otherwise occur.

 

 

"For an attractive force' date=' PE is negative. A bound system has PE + KE <0"

 

Your wrong. [/quote']

 

excuse me? My wrong? How so?

Link to comment
Share on other sites

Its not you, its what you were taught. Quantum mechanics is screwy, its definatly not the final word, but if you want to talk about this stuff "quantum physics" you have to go through "quantum mechanics" as it has been theorized and laid out. Its a theory, simple as that. And no theory is completely void of logical fallicies, but QM seems to have more than its share of them.

 

This whole chapter 3 is textbook QM its all hit and miss, its where you get your PE KE < 0 terminoligy, but where they miss its huge.

http://www.chemistry.mcmaster.ca/esam/Chapter_3/intro.html

 

And if you dont want to even try to answer my questions then fine, or give me the benifit of the doubt and go along with what Im saying, Cause I know you have to know what Im saying at some level, your just ignoring the questions and spewing non relavent textbook knowledge that I can read on the internet anywhere.

Link to comment
Share on other sites

The answer to the orginal question of why electrons stay in assign orbitals is connected to ionization energy. The amount of energy needed to kick a lower orbital electron into higher orbitals is too high. With the orbitals filled there is not potential for higher electrons to fall into lower orbitals and create the energy needed to change places.

 

What is interesting is that once a stable atom is formed the orbitals will remain over a range of temperatures. Since the higher temp should be pumping energy into the system, the electron probably responds with a shift in the orbtial wave function. The Heinssenberg uncertanity principle still applies but at the higher temp there is less uncertainy that it will be closer to next orbtial.

Link to comment
Share on other sites

So in a sense could you say that it is in part the repulsion between electrons in various shells that keeps them in those shells? And in the case of a more simple element, then what?

 

Well that is one thing, yet the question is going back to how electron levels change with photon emmision. Ionization being a case of neither photon absorption or emmison. It almost sounds like, aside from the conventional definition, your describing an alternate additional type of ionization whereby electron - electron collision takes place, correct me if Im wrong.. you use the word temperature thats why I say it..

Link to comment
Share on other sites

Its not you' date=' its what you were taught. Quantum mechanics is screwy, its definatly not the final word, but if you want to talk about this stuff "quantum physics" you have to go through "quantum mechanics" as it has been theorized and laid out. Its a theory, simple as that. And no theory is completely void of logical fallicies, but QM seems to have more than its share of them.

 

This whole chapter 3 is textbook QM its all hit and miss, its where you get your PE KE < 0 terminoligy, but where they miss its huge.

http://www.chemistry.mcmaster.ca/esam/Chapter_3/intro.html

 

And if you dont want to even try to answer my questions then fine, or give me the benifit of the doubt and go along with what Im saying, Cause I know you have to know what Im saying at some level, your just ignoring the questions and spewing non relavent textbook knowledge that I can read on the internet anywhere.[/quote']

 

 

OK, you have a beef with QM. Shall we just have the moderators move this to pseudoscience now?

Link to comment
Share on other sites

No beef with Q.M. here. It's great

 

best.

 

Eon.

 

But I have a further question.

Perhaps Swansont might care to answer or any expert.

I might be way off base. Not sure.

 

My understanding is that an orbital (in the sense of this is how an electron travels around a nucleus) is not a physically viewable or verifiable thing.

Unless it's computer generated to be viewable or drawn onto a graph.

 

Rather an orbital is a mathematical function that puts electrons into a three dimensional world. But the actual electrons may move (fly? spin? appear?) differently from the numerical mathematical function that describes them.

 

Again. An orbital is a mathematical function, (nothing more, nothing less) not a physical thing itself but it does attempt very well to describe chemical bonds, shells and other things that must be of a physical nature.

 

Is my understanding correct?

 

 

best again,

 

Eon.

Link to comment
Share on other sites

My understanding is that QM is a tool for calculating outcomes of certain types of systems. QM has nothing scientific to say about what the systems are like apart from its mathematical constructs. In this way QM is close in spirit to the idea of a hypothesis as it was used by the church ar the time of Galileo. Roughly, hypotheses were useful calculating devices but said nothing about the true nature of systems.

Link to comment
Share on other sites

Eon, "is not a physically viewable or verifiable thing." That is basically correct for casual understanding.

 

Subatomic particles are harmonic oscillators in which whose position and momentum is largely indeterminate in both a sense of practical measurement and observation.

 

It is in essense the extreme velocity of the electrons momentum that gives rise to an aspect of the Uncertaincy Principle. Or at least that is my belief. Keeping in mind that the geometry of the electron particle includes and can often be defined as the charge around it as well. Say the electron was nuetral, well then it is all particle But its a particle with a substantial deformation regardless, again because of its rapid momentum. So either way the electron can be said to be "fuzzy". I would say "orbital" is to be taken literally if and only if the electron is not part of a molecular bond, in such the electron loses that degree of freedom and that in part gives rise to the shape of complex molecules. Whats unique about it is that, take a particle that "vibrates" along the radius axis, and in addition to that add orbital motion. So its not like anything classical orbit in the sense that it has this additional wavemotion. I dont think physics is quite caught onto this yet although, so they explain it as appearing and disappearing into exsistance around a certainty mathmatical probability field.

Link to comment
Share on other sites

New question if none can/wants to answer the original.

 

What is the functional relationship between an electron and a nucleus, protons and nuetrons, that allows it to absorb a photon such that if it does not have this link ie. free electrons, the function ceases to work?

Link to comment
Share on other sites

Thanks for the thoughts. It's all very interesting.

I'm no expert but I remember studying the many different electron orbits in university long ago and the subject is still fascinating.

 

Right now I'm reading some papers on "Relational Quantum Mechanics" defined by the Stanford Encyclopedia of Philosophy as:

"an interpretation of quantum theory which discards the notions of absolute state of a system, absolute value of its physical quantities, or absolute event."

 

best,

 

Eon.

Link to comment
Share on other sites

New question if none can/wants to answer the original.

 

What is the functional relationship between an electron and a nucleus' date=' protons and nuetrons, that allows it to absorb a photon such that if it does not have this link ie. free electrons, the function ceases to work?[/quote']

 

Why does there have to be a relationship between an electron and its nucleus for it to absorb a photon? The reason we like to excite bound electrons is because they are local to some region. The electromagnetic field and electron have a sort of charge-charge interaction. The easiest model to understand is to assume the electron is a damped harmonic oscillator held in place by a spring connected to the nucleus. the charge interaction with an appropriate frequency EM-field (photon) allows the electron to absorb energy through a type of resonance.

Link to comment
Share on other sites

My understanding is that an orbital (in the sense of this is how an electron travels around a nucleus) is not a physically viewable or verifiable thing.

Unless it's computer generated to be viewable or drawn onto a graph.

 

Rather an orbital is a mathematical function that puts electrons into a three dimensional world. But the actual electrons may move (fly? spin? appear?) differently from the numerical mathematical function that describes them.

 

Again. An orbital is a mathematical function' date=' (nothing more, nothing less) not a physical thing itself but it does attempt very well to describe chemical bonds, shells and other things that must be of a physical nature.

 

Is my understanding correct?

 

 

best again,

 

Eon.[/quote']

 

No. Orbitals have been mapped out experimentally. cuprite atoms image from a group at Arizona State U.

Link to comment
Share on other sites

What is the functional relationship between an electron and a nucleus, protons and nuetrons, that allows it to absorb a photon such that if it does not have this link ie. free electrons, the function ceases to work?

 

A free electron can't conserve both energy and momentum by absorbing a photon. So you get Compton scattering instead.

Link to comment
Share on other sites

It is in essense the extreme velocity of the electrons momentum that gives rise to an aspect of the Uncertaincy Principle. Or at least that is my belief. Keeping in mind that the geometry of the electron particle includes and can often be defined as the charge around it as well. Say the electron was nuetral, well then it is all particle

 

Neutrons exhibit wave behavior, as do neutral atoms.

Link to comment
Share on other sites

Compton scattering, exactly. Now answer my question.

 

"Neutrons exhibit wave behavior, as do neutral atoms."

 

I take it this was a reply to my "Say the electron was nuetral, well then it is all particle" statement. Logical fallicy, you assume when I say "all particle" that meant no wave behavior, when I fact Im fully aware of the truth to your statement.

Link to comment
Share on other sites

Lorentz Oscillator model...

http://webphysics.davidson.edu/Projects/AnAntonelli/node5.html#SECTION00500000000000000000

 

Why? So your telling me that a free electron can absorb photons? Will you tell me that it can emit photons then also?

 

I only implied that there is an electromagnetic interaction in what we call absorption (or energy transfer). It has been modeled as a damped harmonic oscillator as you've shown in your link. The damping term 'gamma' and the oscillation frequency 'omega' are descriptions of the electron-nuclear interaction. They basically define the "spring constant" and "damping" of the system. The interesting result is there is interaction with photons that are NEAR the transition frequency "omega_0" (as opposed to exactly "omega_0").

 

However, the point I wanted to make is that the link you post is a description of the dynamics and not of the interaction mechanism itself. There can essentially be other systems (obviously not free electrons) that react to EM radiation (ex: exciton breakdown...otherwise known as stimulated emission).

Link to comment
Share on other sites

Compton scattering, exactly. Now answer my question.

 

"A free electron can't conserve both energy and momentum by absorbing a photon" was insufficient?

 

"Neutrons exhibit wave behavior' date=' as do neutral atoms."

 

I take it this was a reply to my "Say the electron was nuetral, well then it is all particle" statement. Logical fallicy, you assume when I say "all particle" that meant no wave behavior, when I fact Im fully aware of the truth to your statement.[/quote']

 

Well then, perhaps you would explain what you mean, because to me "all particle" carries the implication of "no wave" in the behavior.

Link to comment
Share on other sites

Swansont wrote: No. Orbitals have been mapped out experimentally. cuprite atoms image from a group at Arizona State U.

 

Charge density maps are interesting. Thanks for that link. No they didn't have that technique when I was in university.

 

The images are refined by computer and the unwanted data is culled by a small computer program but yes that’s pretty close to direct observation so it's very cool.

 

I'm convinced, and consensus in the scientific community on the technique appears to be strong.

The computer assisted parts of the process don't seem to interfere too much with the original observations.

 

Very Interesting stuff.

 

Thanks.

 

Eon

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.