Photon-proton/ proton-electron interactions

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  • #1
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hi
i was just curious to find out how photons interact with protons (virtual and real) because as we know a photon excites an electron to a new state but what happens to a proton?

also why dont electrons collide with the nucleus. i know they have acceleration which will keep them from "falling" into the nucleus however if 2 electrons come near each other and repel each other wont one spin closer to the nucleas (in which case its possible for it to spin straight in) while the other is repelled outwards?

ive read two ways that electrons dont collide with the nucleas. one is that photons from the proton keep them excited enough not to come to close to the nucleus (which is why i asked the first question) and if this is the case what happens if a photon misses an electron (and i know electrons arent always particles (even though a recent experiment has proven that electrons exist in 2 states at once)).

the other way that i know of that could be possible is that electrons is an actual electron cloud... a charge spread over an area. this is fine until i think of it being spread through the nucleus. if its a charge being spread then why isnt it attracted to the positive charge of the nucleus? and if it is an electron cloud then s p d f orbitals wont really exist would they?

so any help would be nice
thanks

ps i know that schrodingers equation n cannot = 0
 
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Answers and Replies

  • #2
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An incident foton is absorbed by the target atom if it has just the exact amount of energy in order to trigger the excitation of the atom. This means that one of the electrons is pushed out of it's position leaving a hole. This is the excited state.

A higher positioned (i mean higher qua energy) electron can fill this hole up by emitting some EM-radiation. This is how X-rays are generated.

An electron will not interact directly with the atomic nucleus because of the surrounding electron cloud which yields a repulsive effect,hmm.

The electron cloud is not attracted into the nucleus because the constituent electrons repell themselves. This leads to the equilibrium (attraction by the nucleus and repulsion by the other electrons) that leaves the cloud around the positive nucleus.


This is just of the top of my head, i will post some more answers later on...
till then

regards
marlon
 
  • #3
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in answer

This leads to the equilibrium (attraction by the nucleus and repulsion by the other electrons) that leaves the cloud around the positive nucleus

there must be an electron right at the bottom which is nearest to the nucleus which will be pushed into the nucleus

why doesnt this happen?

and how do protons interact with photons?
 
  • #4
ZapperZ
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I will add just a little bit to what Marlon has said...

no gun said:
hi was just curious to find out how photons interact with protons (virtual and real) because as we know a photon excites an electron to a new state but what happens to a proton?
You need to make sure you understand this clearly. When a photon of the right energy hits an atom, it doesn't "excite" an electron, it excites the WHOLE ATOM. The energy states that the electron can occupy is a result of the combination of the nucleus and the electron, not just the electron alone. We know this to be true because a free electron has no such energy states. So the nucleus plays a significant role in forming those energy states for the electron to occupy. It is the atom that is excited upon photon absorption, not the electron.

Zz.
 
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A cristal clear addendum from ZapperZ

Indeed, the electron has the energylevels described by QM because it is in interaction with the atomic nucleus.

regards
marlon
 
  • #6
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no gun said:
and how do protons interact with photons?
This is an answer i gave in another thread. It describes how electrons interact with EM-waves (photons) due to the Lorentzforce. Every charged particle in an EM will feel this force, so the following explanation is just the same for protons. Just replace electrons by protons when reading



The EM wave (photons) exerts a Lorentzforce onto the electron. This electron accelerates and the momentum goes from p to p''. Part of the momentum of the EM wave is being absorbed by the electron (Poynting vector). Because the electron is accelerated it will emit an EM wave with wavelength lambda'. So basically the incident photon has a wavelength that goes from lambda to lambda'. The momentum of the electron them changes into p'. So we have p --> p'' --> p'

This EM way of thinking is a local fieldtheory because their is no activity of forces "on a distance". EM-forces are being carried over by fields that fill the entire "space" and they interact with charges positioned at a specific place. This is a big difference with the Newton-way of thinking.

It is in complete accordance with the local fieldequations of Maxwell that electrons are pointcharges. This is a consequence of the fact that Maxwell equations need to be relativistically invariant. The only question remains as to why the entire EM-wave is absorbed as one single quantum. The answer to that question is ofcourse the wave-mechanics of Schrödinger...as we all know...(first quantization)

So we have fields, and particles and it is the second quantization that gives us force carriers (viewed at as particles not as waves) and the fermionic matterfields (like the Diracfield being the general solution to the Dirac-equation)that yield the elementary massless particles of the Standard Model.

regards
marlon :cool:
 
  • #7
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i still dont understand how the whole atom is excited when its just one electron rising a shell then dropping a shell once it releases the photon. the atom doesnt change just the electron.

if a photon does not interact with a electron directly but does with a proton, will the fact that a proton is so large mean that it will just reflect the photon?
also why doesnt the electron hit the nucleus? :P dat was da main question

if the orbital of an electron is slightly changed due to repulsive forces from another electron wont that be enough for the electron to spiral into the nucleus (just like a satellite). in addition to the attractive force of the proton (which is quite large)

so 3 question in summary :D
1) how do proton directly interact with photons (reflect or absorb?)
2) why dont the electrons collide with the nucleus in any case senario?
3) how is the whole atom effected when a single electron is excited and de-excited

thanks :D
 
  • #8
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no gun said:
i still dont understand how the whole atom is excited when its just one electron rising a shell then dropping a shell once it releases the photon. the atom doesnt change just the electron.
Those "shell" that you talk about came about when you solve the schrodinger equation for a central, spherical potential. This is the NUCLEUS of the atom! Without the atom, there are no shells, no energy states, etc.

There are no "absorption" of a photon by a free electron. There are scattering of a photon by free electrons. Thus, the electron in an atom are "incidentals". It is the whole atom that gained energy, not just the electron making the transition. When you exercise, you say that your whole body becomes warmer. Yet, technically, only certain parts of your body that are exerting most of the effect. Yet, you make no such distinction of what parts of your body are warmer and more "excited". You say your whole body systemically are warmer/hotter.

Same thing with the atom....

Zz.
 
  • #9
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so in other words the reason for an electron not hittin the nucleus is the fact that it is always excited because of constant photon interactions?

and if we were able to stop these photons then what?
 
  • #10
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no gun said:
so in other words the reason for an electron not hittin the nucleus is the fact that it is always excited because of constant photon interactions?

and if we were able to stop these photons then what?
I don't think so. The electron and the nucleus underdo many interactions. They are both charged so they we exert a Coulomb-interaction onto eachother. If you would look at the corresponding potential, you will see that this potential has a minimal value when plotted in function of the distance r between the two interaction particles. This minimum in potential energy denotes the binding-state because everything in nature will strive to be in the state of lowest potential energy. You could say that nature is as lazy as possible. Now, the distance r corresponding to this lowest potential energy is NOT 0 but has a certain finite radius (the Bohr-radius for example) , thus the electron has a minimal distance to the nucleus that is equal to this r-value.

Keep also in mind that two things have to be taken into account. First you have the "attraction" between the electron-cloud and the nucleus, but the electrons themselves are repelled because of the many electrons that make up the cloud surrounding the nucleus.

An atom does not need photons hitting it in order to be in this stabe equilibrium.

Finally, stopping a photon (or changing it's path) would require extern magnetic fields in order to exert a Lorentz-force on it. ofcourse this also brings a change in the energy-levels of the atom (e.g. The Starck and Zeemann-effect). Let's not do that... :smile:

regards
marlon
 
  • #11
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ok thanks ... still doesnt seem to logical to me but i guess ill have to deal with it
 
  • #12
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What is it, that maken this look unlogical to you...

I will try to explain to you...

regards
marlon
 
  • #13
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Hello, I got the same question. But for simplicity, lets talk about hydrogen atom, with one proton and one electron (so there is not electron cloud, just 1 electron). Why electron doesn't collide with nucleus (proton), but keeps orbiting around it? (There is an acceleration, but lets assume that sooner or later it is gone be externaly disrupted in a way that electron is gone be pushed towards nucleus).
 
  • #14
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Hello, I got the same question. But for simplicity, lets talk about hydrogen atom, with one proton and one electron (so there is not electron cloud, just 1 electron). Why electron doesn't collide with nucleus (proton), but keeps orbiting around it? (There is an acceleration, but lets assume that sooner or later it is gone be externaly disrupted in a way that electron is gone be pushed towards nucleus).
Check out the answer to your question : https://www.physicsforums.com/showpost.php?p=862093&postcount=2 [Broken]


marlon
 
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  • #15
The electron cloud is not attracted into the nucleus because the constituent electrons repell themselves. This leads to the equilibrium (attraction by the nucleus and repulsion by the other electrons) that leaves the cloud around the positive nucleus.
How does this relationship work in say, Hydrogen, when there is only one electron?
If the electron exists as a smeared cloud, precluding it from contacting the nucleus indefinately, then neutron stars could not exist, as this process of annihilation between the protons and electrons would be necessary for that. If the electrons do not exist as a solid tangible mass, succeptible to the laws of physics, how do they succumb to pressure and gravity, eventually "falling" into the nucleus in the collapse of a neutron star?
Bear in mind I am not a physicist, so please forgive me if my questions seem unintelligent.
 
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  • #16
OMG, thank you all so much!
I've been doing research because I am writing a science fiction book about superheroes, and I wanted to use some form of realism in my story so I started doing some research. My character uses electromagnetic radiation for her super powers, and I needed to know what would happen if certain elements collided with her energy force fields, or if she shot the energy off as a beam, what the effects would be. I needed to know more about photons and electrons, and how everything involved in EM radiation worked. I think this topic gave me a very good idea of the results and how her powers should be. For the most part I understood everything that was posted. I think I'm going to bookmark this site and lurk around a bit. I'm now very interested in learning more about science....
^_______^
 
  • #17
Drakkith
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How does this relationship work in say, Hydrogen, when there is only one electron?
If the electron exists as a smeared cloud, precluding it from contacting the nucleus indefinately, then neutron stars could not exist, as this process of annihilation between the protons and electrons would be necessary for that. If the electrons do not exist as a solid tangible mass, succeptible to the laws of physics, how do they succumb to pressure and gravity, eventually "falling" into the nucleus in the collapse of a neutron star?
Bear in mind I am not a physicist, so please forgive me if my questions seem unintelligent.
Electrons are neither small balls orbiting the nucleus nor are they "clouds". They exist as a wafe form with a probability of being detected in certain spots around the nucleus based on the energy level they currently occupy. Oddly enough, there IS a small probability of the electron being INSIDE the nucleus. The electron isn't captured by the proton because that would result in then proton turning into a neutron, which would be less favorable for the nucleus than simply keeping the proton and the electron seperate. The full description would involve lots of math and formulas, and unfortunantly I'm not familiar enough with them to explain.

But be aware that electrons follow the laws of physics 100% to the letter. The way you think of the world at our scale is NOT the way it actually is when you get down near the atomic scale.

OMG, thank you all so much!
I've been doing research because I am writing a science fiction book about superheroes, and I wanted to use some form of realism in my story so I started doing some research. My character uses electromagnetic radiation for her super powers, and I needed to know what would happen if certain elements collided with her energy force fields, or if she shot the energy off as a beam, what the effects would be. I needed to know more about photons and electrons, and how everything involved in EM radiation worked. I think this topic gave me a very good idea of the results and how her powers should be. For the most part I understood everything that was posted. I think I'm going to bookmark this site and lurk around a bit. I'm now very interested in learning more about science....
^_______^
Good luck with your book! Just be aware that you need to take EXTREME liberties with physics in a book like this usually lol. Otherwise where's the fun at?
 
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  • #18
Hello, everyone!

I made a post a few weeks ago about how I was writing a book and I was using this forum as reference. I've been doing a lot of research on EM waves, protons, and photons, but I am not a physicist. I've only been studying for about six to seven months now (because that was when I started writing my story). My character is able to manipulate, absorb, and alter electromagnetic energy that is around her, and can bend it/shoot it in a variation of ways.
Such as focusing it into plasma shields, plasma beams, or force fields.
I've been having trouble trying to figure out what all she can repel with her EM waves, and so I started testing it out in different ways.

So before I actually started writing the book I've been role playing my character out on another site to test out her powers. Below is a Role play battle I am having against another guy and his hero. I did not include his post though.
Now I've been reading about photon interactions and EM waves, and I would like you to read my post and to tell me if what I wrote is "logical".

I know superheroes are not realistic, but I would like my hero's powers to make sense. I want my book to include some form of realism to it. I am going to continue to study and learn, but because I do not know any scientist in real life, I would like your feed back on what I came up with. Does the below post make sense with what she did and how she repelled the force of energy?

I think you can figure out what had happen prior to her attack based on how I wrote it out. Thanks in advance.

Glory only had time to smirk as the ball of dark matter came towards her. She had seen something similar to this before a long time ago, and because of this, she knew exactly how to counter it. Glory's tactic was simple, observe, and then counter. She had learned how he used his powers, and now all she had to do was counter it. Most of the time her opponents were a lot more simple and it didn't take this long, but it didn't matter. What she was going to do was turn his own power against him. How? Well, it was all quite complex, but looking at it would be very simple. The first thing she did was clench her hand tight, the one that was up in the air, and let the power flow through her body, and outwards. The effect looked like her hand was struck by a bolt of lightning that sent a shock wave outwards around her. The moment her power was set free both her arms clenched and bent to her sides and she let out a scream of pure agony as every muscle in her body constricted from the surge of power. There was a thick vein in her neck that could be seen popping out as the current ran through her body and converted into force. Her back arched and her head snapped back as she howled towards the sky. Her legs straining to stay upright.

The reason Glory HAS to wear the suit is not to protect her from outside damage, but from harming herself. It was very rare that a sensitive was immune to their own powers. Having said that, every single time Glory uses her own ability, it pains her to do so. The suit helps to channel her powers around her body, instead of it flowing straight through. Even with the suit though, it still hurts.

And the reason she shot her power out in a wave the way she did was because she needed to create an electromagnetic force field around herself. Much like the plasma shield earlier, but this one was made of pure gravitational force. Imagine anything coming towards her was a north magenet, and the force field around her was also a north magnet. Now imagine that the object in question was coming towards her at an extremely fast speed (which would create a large amount of energy from its momentum), the magnet would stop the object, repelling it backwards as the energy came it contact with it, and send it flying back the way it came. That was what she was doing, and that was why she had to shoot the wave off. It looked similar to the EMP she had shot off earlier but this time it was a continious surge of energy to make sure nothing could pass through the field. The wave of energy didn't go far, perhaps ten feet around her in a circle.

The orb Lewis shot resembled a black hole, dark matter, or a gravity ball that would cause the target to implode upon impact. Such force was creating vibrations, and those vibrations were creating energy, it was this energy that she targeted to repulse. Not the orb itself, but the vacuum of energy that surrounded the ball.
So to explain it simply: what she was doing was repelling the magnetic force the ball was creating, I.E. the gravitational field that was compressing the ball, and using its own momentum and force to turn it back the way it came, which just so happened to be Lewis. The whole thing happened as fast as it took for her to clench her fist. The field around her popped and sizzled as it stayed contained in its small ten foot orb.
As the ball came towards her it got caught in the field, and the instant it stopped, all that force was sent back the opposite way at twice the speed. Just like a toy Guass gun that shoots off those little metal marbles...


Glory's hair was now a giant frizz ball, and her skin was being charred. Because she was naturally stronger than the average human though, it would take a lot more then this in order for the effects to actually visibly appear. Even so, if she kept it up she was going to probably suffer second degree burns from her own attack...

PS: I will probably be asking follow up questions about EM waves and photons as you post to better understand everything. Small bits of realism in books always makes those daring escapes all the more fun when people can follow the chain of logic.Otherwise it is just nonsense.
 
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  • #19
Drakkith
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Why is her gravity forcefield repelling things? Gravity is only attractive.
 
  • #20
Alright, perhaps I worded it wrong? Should I have said magnetic force?
But I still run into a problem...

I have tried doing research but as I said, I'm having trouble when it comes to her powers repelling things. If gravity can only attract, what force would be required to repel?
I tried going to youtube to see if I could find something that was forcing objects away, but that was no good. I just found this, but I don't think it is real.

The whole thing is complicated because the guy in the fight is shooting some type of gravity ball at her, so lets take that out and replace it with something more simple.
Lets instead replace it with a person.

I have never seen a real life force field so I'm not sure what would happen. I read that plasma can work as a shield to keep particles out, like on a spacecraft, but it wouldn't actually repel the object, the plasma would just destroy the object trying to pass through, right?

So hypothetically speaking, how would she go about reflecting matter?
Is there a real life machine that can do what I am asking?
On magnets the same poles repel each other (like north and north), but how would this be applied to other objects that are not magnets, like people?

So lets say that there are two giant magnets lodged in the ground, both are of the same "north" magnets and facing each other and repelling away. If these magnets were extremely powerful, what would be the effect of something (a person) moving in the center of the field?
Would they be smashed from the force, or just hit a barrier?
Or perhaps the waves would have no effect on a person at all?

I guess what I am asking is, would it be possible for her EM waves (or field) to repel photons and particles in way that can work on large objects like people and nonmetal projectiles?

If I am to write the book I'm going to need to understand how this works.
 
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  • #21
Drakkith
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So hypothetically speaking, how would she go about reflecting matter?
I can't really answer that as it isn't physically possible.

At VERY strong magnetic strengths, you can affect materiels that are normally unaffected by magnetic fields, but I don't know any details. At the very strongest sources of magnetic fields, magnetars (which are neutron stars) the fields are so high that they rip apart matter and do other crazy things. See here: http://en.wikipedia.org/wiki/Magnetar

I guess what I am asking is, would it be possible for her EM waves (or field) to repel photons and particles in way that can work on large objects like people and nonmetal projectiles?
Well, an EM field is NOT composed of waves. It can have waves in it, but is not made of fields. It is probably possible that you could magnetic fields to repel things, but it really depends on a lot of variables. I suggest not even really working them out too far as you just get bogged down in the story.
 
  • #22
So hypothetically speaking, how would she go about reflecting matter?
I can't really answer that as it isn't physically possible.
Ahaha, yeah...
I guess I'll continue to study. Thanks for your input. I guess I'll just skip out on certain fine details when she has to use them if I can't find any more info...

If someone else can help me out that would be awesome.
I have already studied magnetars, but again that is force that destroys stuff, like her plasma shield, and it doesn't push things away from her.

I was kinda hoping she could use her force fields in ways to like create a "bubble" around herself to keep a falling building from crushing her, without disintegrating it. Or smashing a person up against a wall with her force field without them dying from it, just to hold them in place. Or perhaps put the shield up to stop a car from running her over so it hits a "brick wall" of force.
I guess like they always do in Sci-fi movies when they have those transparent force field doors to hold prisoners, or to keep people from being sucked out into space....

Oh well, thanks again. I'll check back from time to time to ask more questions.
Until then, I'll continue to read!
 
  • #23
Drakkith
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The problem is that there isn't a force that is ONLY repulsive. An electromagnetic field is repulsive is repulsive to one charge and attractive to the other all at the same time.

However...you COULD make her so that she projects a gravity field BEHIND whatever is coming at her, causing it to stop.
 
  • #24
Hmm... I see... what you are saying.

So if she used the gravity field it would be pulling the object away from her?
Hmm, yeah I guess...

Lets look at this then in another way. Looking at it in the form of super powers complicates things. Perhaps she wouldn't have to actually "repulse" objects away from her, but create a large amount of force to "knock" it away from her.

Magnetars create magnetic fields, yes?
But as we said it destroys stuff in crazy ways.
I want to get away from destruction. There is no point in being a hero if you destroy everything around you. But perhaps we can use this concept. From what I understand it spins at extreme speeds and that is what creates the chaotic magnetic field.

So, EM radiation is made up of photons, right? And when this is concentrated and gathered it can turn into plasma (like lightning)?
This is correct, yes?

Can a plasma ball be created without "burning" or electrocuting? Like a very weak plasma beam?
I have never seen anything interact with plasma, as in coming in contact with it. I assume it burns because it is like an intense flame or a very strong current of energy...
I am getting to a point and I need to know if it makes sense.

I'm not sure if I understand this right, so please correct me if I am wrong.
So what if a machine created a gravity field around itself by generating a large amount of Electromagnetic radiation and began spinning it around at extreme speeds, could it really create a small gravity field? Like a fake, small scale magnetar that is spinning around in a contained area. If so, would the EM radiation that is spinning turn in to plasma?
I assume this would still be harmful if something came in contact with it...

Would it be possible for this gravity field to grab a object caught in the field, much like what a planet does when something is caught in its orbit, and then slingshot the object around and back outwards?
So that it "spins" the object away from the machine. If it is fast enough and it doesn't lose control, anything that tried passing through the force field would be thrown back by the intense rotation speed.

That way it is still being "repulsed" back the way it came. I just need to know if plasma "always" burns. Can it be a "blunt" force?
If it does always burn, what would need to be created to get the gravitational force going without using plasma? Or is this not possible?

If it turns out she is bound to be destructive I can work with that.
 
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  • #25
Drakkith
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Plasma is very very hot AND has a very very low density usually. It would be harder to knock something away with it than it is with air. And if you have enough of it to do so, it would burn the crap out of it!

I'm not sure if I understand this right, so please correct me if I am wrong.
So what if a machine created a gravity field around itself by generating a large amount of Electromagnetic radiation and began spinning it around at extreme speeds, could it create a small gravity field? And if so, would the EM radiation turn it into plasma?
I hope not, because what I understand about plasma is that it is hot and burns...
Gravity is generated from mass/momentum. The EM radiation would create gravity, but the whole idea is impossible in practice and would require so much energy it is unimaginable. It is impossible to generate a gravity field of sufficient strength without invoking superhero powers. But thats why you have those powers! To do cool stuff!
 

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