Do just electrons emit photons?

[desta41]

Do just electrons emit photons/radiation. Or do atoms and molecules emit photons as well? Just can't get a clear answer on this.

And if atoms and/or molecules also emit photons, can you please explain what causes them to?

 

[Bystander]

https://en.wikipedia.org/wiki/Black-body_radiation

 

[desta41]

https://en.wikipedia.org/wiki/Black-body_radiation

Good information, but what I'm asking about is not covered there. I need a specific answer regarding whether molecules and atoms, themselves, emit photons. I know electrons emit photons, but do molecules emit them as well? And speaking of blackbody radiation, is that emitted from just electrons or from both electrons and molecules?

 

[mathman]

Radioactive (nuclei) decay leads to gamma ray production.

https://en.wikipedia.org/wiki/Thermal_radiation This describes lower energy sources.

 

[Bystander]

Re-read the part of the article on "cavity radiation."

 

[ZapperZ]

Do just electrons emit photons/radiation. Or do atoms and molecules emit photons as well? Just can't get a clear answer on this.

And if atoms and/or molecules also emit photons, can you please explain what causes them to?

If I take a bunch of protons and jiggle it up and down, I can generate light.

ANY accelerated charge will create EM radiation.

Zz.

 

[blue_leaf77]

I know electrons emit photons, but do molecules emit them as well?

I would say in most cases, the emission of photons always follow from some mechanism in which a change in energy of the atomic / particle system occurs - simply as a consequence of energy conservation. So, if atoms or molecules relaxate they will emit photons.

 

[desta41]

What about when a molecule rotates? Or the stretching of molecular bonds? Would those occurances cause radiation? Two things examples of molecules radiating (and not the electrons and protons as the cause)...

 

[sophiecentaur]

What about when a molecule rotates? Or the stretching of molecular bonds? Would those occurances cause radiation? Two things examples of molecules radiating (and not the electrons and protons as the cause)...

I thought a molecule was made up of electrons and protons? The actual energy of the photons depends upon the energy change involved.

 

[desta41]

I thought a molecule was made up of electrons and protons?

Yes, of course. I was just meaning the rotation and stretching of the molecule causing radiation. Not the charge from electrons or protons. Is radiation just caused from electrons and protons then? Not from rotating or stretching molecules?

 

[sophiecentaur]

Bending and stretching and rotating a molecule alters the arrangement of the electrons and protons - what else? Changing the arrangement of charges will involve radiation. Why would you think otherwise? It is a pretty consistent model.

I guess it's worth pointing out that a molecule that is rotating will only radiate (or accept) a photon if there is a permissible transition in its energy states. But that's the same as with an 'orbiting' electron.

 

[desta41]

When in an atom, I was caught into thinking that the electrons jumping down energy levels was just the cause of radiation. But makes sense, then, that bending, stretching, and rotating of the molecules leads to the electrons emiting photons.

So is blackbody radiation due more to the electrons continuously jumping down energy levels and therefore radiating photons, or from the aforementioned types of molecular movements causing the electrons to emit radiation? Or both?

 

[sophiecentaur]

When in an atom, I was caught into thinking that the electrons jumping down energy levels was just the cause of radiation. But makes sense, then, that bending, stretching, and rotating of the molecules leads to the electrons emiting photons.

So is blackbody radiation due more to the electrons continuously jumping down energy levels and therefore radiating photons, or from the aforementioned types of molecular movements causing the electrons to emit radiation? Or both?

You seem to insist on talking in terms of 'electrons'. This will be because, as with everyone else, you got The Hydrogen Atom in your introduction to QM. Whilst everything contains electrons, the way it works is not as simple as The Hydrogen Atom. The energy states in a single atom all involved relatively big gaps and will not involve all frequencies of radiation. With molecules and densely packed matter (solids and liquids) there are many more combinations of charges and you have to include everything in a model to describe how the radiation interacts with the system. It's to do with the states of all the charged particles in a molecule, relative to each other that explains the frequencies that are absorbed and radiated. In condensed matter, you don't have discrete levels but whole continuous bands of energy, which is why you get continuous spectra and not lines in a 'red hot' object.
Bottom line is that you need to not hang on to the simple models if you want to get to understand the more advance phenomena. For example, you cannot explain how light is reflected coherently from a shiny metal surface if you model it on one photon exciting one electron on the metal surface and then a photon being re-emitted. That would never produce a specular reflection because of the random delay in the absorption / emission process. It has to involve a large region of the surface, with gazillions of electrons involved.

 

[desta41]

I appreciate your expanding on this matter. I feel as if I have a better understanding.

So would it be fair to say, then, that, thermal radiation from an object (not from an ideal blackbody) has little or nothing to do with electrons jumping or changing energy levels in an atom? It would be all or mostly from rotation and vibration of molecules (which, of course, involves the altered arrangement of electrons and protons)?

Question #2: Let's take a brick in the sunlight. If you were to say that it's the molecules of the brick that absorb the photons, couldn't it be said that, technically, the electrons are absorbing them as well since the molecules contain electrons?

 

[ZapperZ]

I appreciate your expanding on this matter. I feel as if I have a better understanding.

So would it be fair to say, then, that, thermal radiation from an object (not from an ideal blackbody) has little or nothing to do with electrons jumping or changing energy levels in an atom? It would be all or mostly from rotation and vibration of molecules (which, of course, involves the altered arrangement of electrons and protons)?

Question #2: Let's take a brick in the sunlight. If you were to say that it's the molecules of the brick that absorb the photons, couldn't it be said that, technically, the electrons are absorbing them as well since the molecules contain electrons?

Unfortunately, this is a very common theme here in this forum, and it requires another explanation why we have such a field of study as solid-state physics and condensed matter physics.

When atoms and molecules are clumped together into a solid, they form a conglomerate in which the characteristics of the solid are predominately due to the collective behavior of all these atoms and molecules. What that means is that the individual behavior of the atoms and molecules are often no longer apparent in the properties of the solids.

One important emergent, collective property that a solid has that are not found in isolated atoms and molecules is presence of phonons. This is a vibrational modes of a solid due to the gazillion atoms and molecules that make up the solid. In fact, phonons are responsible for a large range of properties of the solid, ranging from optical to thermal to electric transport.

The reason I brought this up is because if you learn solid state physics, and especially the http://www.uni-tuebingen.de/meso/ssscript/phononen.pdf , you will discover that the phonon or vibrational modes have two branches - the acoustic and the optical modes.

The optical modes are "electromagnetically active". It is basically a dipole mode, and this mode can not only absorb EM radiation, but can also, under the right condition, emits EM radiation (it is often called Raman active). This property is often attributed to why we see colors from different objects.

So when you heat, say, a tungsten wire in an incandescent light bulb, if you look at the spectrum using the spectroscope that we give students in many intro physics laboratory, you will see a continuous spectrum of color, instead of a set of discrete lines that is expected from atomic transition. The heat causes all these vibrational modes of a solid to be enhanced to the point where the EM radiation they emit is intense enough to be seen. This is why the spectrum of light given off is different than from atomic gasses.

Moral of the story here: More Is Different (Phil Anderson)!

Zz.

 

[sophiecentaur]

couldn't it be said that, technically, the electrons are absorbing them as well since the molecules contain electrons?

You can say what you like. Your version has some aspects of truth in it. But if you insist on your particular, partial explanation then you will find it harder and harder to explain all the EM absorption and emission phenomena there are.
Instead of trying to hang on to your basic idea, seemingly at all costs, I recommend that you make an effort to learn a bit more Physics. Why do you come to PF if you just want to be 'right' all the time?

 

[desta41]

Unfortunately, this is a very common theme here in this forum, and it requires another explanation why we have such a field of study as solid-state physics and condensed matter physics.

I more than appreciate your response. I've heard, though, that a real-life blackbody (not an ideal or perfect one) will show spectral lines. And I've heard that some studies in astronomy use this kind of blackbody analysis--e.g. relative intensities and spectral lines--to infer information about stars. Perhaps I'm missing something big here. But, if I'm understanding you correctly, thermal radiation, from objects, would just involve molecular vibrations and not jumping of electrons? Or can it be both for when it comes to a non-ideal blackbody?

 

[desta41]

Instead of trying to hang on to your basic idea, seemingly at all costs, I recommend that you make an effort to learn a bit more Physics. Why do you come to PF if you just want to be 'right' all the time?

In no way am I trying to be right. I am just trying to get a full understanding and throwing some things out there for analysis. I really appreciate the long answer you gave me and I feel it has helped. Was just wondering about that one other way of looking at it, that's all.

 

[sophiecentaur]

And I've heard that some studies in astronomy use this kind of blackbody analysis--e.g. relative intensities and spectral lines--to infer information about stars.

I think you may be referring to the absorption lines, caused when the black body light emitted from a star shines through its outer atmosphere (rarified gas with single atoms or molecules where the energy levels are discrete). The Helium Lines were spotted in sunlight - for the first time and that was why the name Helium was chosen for the newly found element, or so I believe.
New phenomena need new ways of looking at things and the simple 'electrons radiate EM' approach is just not enough. Do a bit more reading round instead of endless Q and A, which can be very inefficient use of your time if you want the bigger picture.

 

[desta41]

I think you may be referring to the absorption lines, caused when the black body light emitted from a star shines through its outer atmosphere (rarified gas with single atoms or molecules where the energy levels are discrete).

Yes, thank you for clearing that up about absorption lines. And, I hear you about reading up more. Let me just close by presenting you one other thing.

What may have been confusing me in regard to whether it's the electron jumps or molecular rotations and vibrations causing the emission of photons is the following (received from an associate):
'In solids, liquids, and gases simple scattering of the molecules transfers the kinetic energy of one molecule to the potential energy of another, i.e. raises an electron to a higher level. The electron goes back to its ground state releasing a specific photon, or a cascade of photons, depending on the energy. Remember that the higher levels with respect to n, the radial quantum number, are closely packed. These photons are the ones emitted as blackbody radiation, and they are a continuum because of the 10^23 molecules per mole and the almost continuous energy levels.'

The part that says, 'The electron goes back to its ground state releasing a specific photon, or a cascade of photons', seems to contradict the idea of blackbody radiation and a continuum, and of molecular vibrations as being the cause for emiting.

If you can shed any light on that quote, I'd be more than grateful.

 

[sophiecentaur]

i.e. raises an electron to a higher level.

You really don't want to let this one go, do you?
Answer me this: A Hydrogen Atom consists of just one Proton and One Electron. When, in the simple, quasi-mechanical model, the electron is disturbed in its 'orbit', what happens to the Proton? Does it stay where it is? Relative to the centre of mass, if one moves in one direction, doesn't the other move in the opposite direction. Doesn't the proton count in this? You could say that, as the proton is 2000 times as massive as the electron, you can ignore it but there would be a finite effect.

It is the energy state of the whole system - molecule or lump of metal, that counts in all em/charge interactions. It is only in the simplest cases that your electron idea can be used as a near-enough model.

PF can answer your randomly directed questions till we are all blue in the face. Do you have access to any textbooks? You do not need "papers" to help you educate yourself because they will either be trivial and possibly incorrect or way over your head. What you need is to have the information presented to you in a suitable order to get a logical sequence of ideas that can give you some understanding. I know that plain reading is not fashionable but I can definitely assert that the only students of mine (A level) who ever got far in Physics were the ones who used their Text Books and read around. Many of the others would rather waste a lesson on misdirected questions because they enjoyed a chat rather than doing actual work. Personal models of QM are doomed to failure. (I think I may safely say).

 

[desta41]

I am definitely aware that it's the whole system. I was mainly trying to determine what the primary contributor to thermal radiation (of most objects) was: the electrons, as a whole, and their jumps, or the molecular vibrations and rotations with moving dipole charge.

 

[sophiecentaur]

Why are you drawing a distinction? In what real situation do you ever just get an isolated electron 'jumping'? Answer: When a free electron is buzzing around in a rarified gas and can be accelerated by an applied magnetic or electric field.
On other situations it is a bit more 'obvious' that there are other charged particles involved - i.e. a charge system and not an individual electron. Even in the first example, there has to have been some other charge involved to cause that event.
If you are talking of an 'object' you never have the situation of an isolated electron.

the electrons, as a whole, and their jumps

I'm not sure what you mean by this.??

 

[desta41]

I don't mean an isolated electron. I'm thinking of the massive amount of electrons that make up an object (say, a piece of wood). There, of course, would be billions of atoms making up the piece of wood, and would be a number of electrons in a good percentage of the atoms that make up the wood. I'm thinking how the electrons, when they absorb photons, become excited and jump to higher energy levels, then, how they release photons as they lose energy and fall to lower states. I'm thinking of all those electrons collectively and how those released photons would likely be considered thermal radiation.

I'm also thinking of the molecular vibrations and rotations of that piece of wood and the moving dipoles of the molecules and how this aspect contributes to emitted thermal radiation.

For each of the two types mentioned above (ways to emit thermal radiation), I'm looking at this in a collective sense; no instance of an isolated electron.

I hope you see what I'm trying to express.

 

[sophiecentaur]

You are asking for a description of the detailed energy levels corresponding to all the structures in a solid object. One thing I can be pretty sure of is that there won't be any rotation in a solid. It's already beenmentined that we are dealing with Solid State Physics here. You need to find out about that. Read a book and be prepared to do some Maths.

 

[desta41]

I know, a lot to study. I had wanted to add this as part of my last reply. I included two quotes from this wikipedia page: https://en.m.wikipedia.org/wiki/Energy_level -- they are discussing the three types of energy transitions for a molecule:'Electrons in atoms and molecules can change (make transitions in) energy levels by emitting or absorbing a photon (of electromagnetic radiation) whose energy must be exactly equal to the energy difference between the two levels.''Molecules can also undergo transitions in their vibrational or rotational energy levels.'What I get from this is, there are three types of ways photons or thermal radiation can be absorbed and emitted.

If I've assumed wrong, please let me know. But, yes, I will definitely be doing plenty of research as time permits.

 

[DrClaude]

Let me first repeat two very important points that were already mentioned. First, it is not the electron in an atom that absorbs/emits a photon, it is the combined system electron + nucleus. Because of the mass difference, the problem is often simplified by considering the nucleus to be fixed, such that only the motion of the electron is considered, but with the presence of the nucleus, there would be no net change of the state of the electron. Second, solids can't be viewed simply as a collection of atoms. Therefore, my answer below is valid for isolated atoms or molecules, or in the gas phase.

'Molecules can also undergo transitions in their vibrational or rotational energy levels.'

This is an oversimplification. At the very core of quantum theory, you can describe the overall state of the molecule, and consider transitions between those states. By introducing approximations, you can separate the electronic motion from nuclear motion (Born-Oppenheimer approximation), and consider electronic states independently from the motion of the nuclei. For the latter, you can make other approximations to separate the overall orientation of the molecule from the relative positions of the nuclei, hence separating rotation from vibration. But these are approximations. One thing that is important to note is that there is no such thing as a pure vibrational transition. Within a given electronic state, you have ro-vibrational transitions, where the rotational state changes at the same time as the vibrational state. The simple explanation for this is conservation of angular momentum: the photon has spin angular momentum, and thus the molecule must gain/lose that angular momentum when it absorbs/emits a photon. Pure rotational transitions are however possible. Likewise, since vibrational states are a subset of electronic states, an electronic transition is always accompanied by a change of vibrational state.

The splitting into three categories of transitions is also related to the fact that they are distinct spectroscopically. Electronic transitions are typically in the UV-Vis part of the EM spectrum, ro-vibrational in the infra-red, and pure rotational in the microwave.

For isolated atoms or molecules, these transitions appear at precise, discrete photon energies. But already in the gas phase, the presence of other atoms or molecules will shift the energy levels, for instance because of collisions or the Doppler effect. For high enough densities and temperatures, the absorption/emission spectrum becomes continuous.

 

[sophiecentaur]

It's also worth pointing out that the 'electron / photon' theory is based on the Bohr Atom model and that is more than a hundred years old. No surprise that it fails to explain a lot of phenomena that have since been dealt with.

 

[desta41]

it is not the electron in an atom that absorbs/emits a photon, it is the combined system electron + nucleus

Thank you so much for your in-depth answer. First off, regarding the above, do you mean that the combined system (electron + nucleus) absorbs/emits the same photon? And, when you say 'combined system', that would be similar to just saying 'atom' (or molecule)?

Likewise, since vibrational states are a subset of electronic states, an electronic transition is always accompanied by a change of vibrational state

And the rotational state would change at the same time as the vibrational state, correct (referring back to your mentioning ro-vibrational transitions)?

Second, solids can't be viewed simply as a collection of atoms

Could you expand on that?

Therefore, my answer below is valid for isolated atoms or molecules, or in the gas phase.

What about solids, liquids, and compressed gases? What would be the best descriptive (since they would likely all contain electronic, vibrational, and rotational states)? Would it be to just not consider any separations?

 

[morrobay]

http://hyperphysics.phy-astr.gsu.edu/hbase/mod3.html#c3
Molecular translation. rotation and vibration correspond to absorption and photon emission in infrared part of EM spectrum . Also see infrared spectroscopy

 

[desta41]

http://hyperphysics.phy-astr.gsu.edu/hbase/mod3.html#c3
Molecular translation. rotation and vibration correspond to absorption and photon emission in infrared part of EM spectrum . Also see infrared spectroscopy

Thanks for that link. I had that site bookmarked awhile back and lost it. Now found.

 

[sophiecentaur]

First off, regarding the above, do you mean that the combined system (electron + nucleus) absorbs/emits the same photon?

You still seem determined to see this in your own terms. You don't seem to be getting the meaning of "combined system". Take a totally different context. A tuning fork emits a specific frequency of sound as the two arms move symmetrically about their mid point. Which of the two arms of the fork is responsible for emitting that sound? Would it make any difference to the resulting sound if you took away the right hand or the left hand arm? The two arms constitute the "system" and they do not operate apart. The same thing applies in an H atom despite the fact that the electron and proton are different masses.
You are locked into a misconception and, until you shift it, you will keep asking questions and ignoring the answers you are getting because they are not consistent with that misconception. Your own personal view of Physics could just possibly be wrong? Has anyone ever told you, in the past, something that convinces you that your model is the right one and that, somehow PF will help you reconcile it with accepted Science?

 

[Vanadium 50]

To build on sophiecentaur: "What is the sound of one hand clapping?"

 

[sophiecentaur]

To build on sophiecentaur: "What is the sound of one hand clapping?"

OMG. Don't go all David Caradine on us!

 

[desta41]

You still seem determined to see this in your own terms.

What is wrong with asking specific questions about the categories of transitions and how everything works together? This has nothing to do with seeing things in my own terms. As I stated in one of my responses the other day, I am looking at the system as a collective and was not taking about an isolated atom or molecule (you are simply misunderstanding me, my intentions, and what I'm about -- not appreciated). I'm specifically interested in completely understanding the electronic, vibrational, and rotational transitions within molecules of solids. They all exist, do they not?

 

[sophiecentaur]

questions about the categories of transitions

Personally, I always see categorising as seriously getting in the way of understanding. Your first category (electrons producing photons) is not a realistic one (for the reasons you have been given by me and others). The vibrational category is limited to isolated molecules (at least, the way you are thinking of it). Can you suggest a rotational transition that can exist at all in a solid?
This is your own personal sub-set of Physics and I suggest you read a (modern) textbook that deals with the solid state and that may give you a clue as to why your model doesn't explain enough of what we see around us.
You want to use your model to explain black body radiation. A monatomic gas at high temperature cannot produce a black body spectrum. The colours you would see if you took an envelope of Hydrogen gas and somehow put it in thermal equilibrium (i.e. heat it up) in a furnace at 1000°C. Would you expect it to be 'red hot'?
Yo get black body spectrum, you need a condensed arrangement of atoms so that transitions are 'available' amongst all the energy bands. This stuff is way beyond the elementary behaviour of idealised gaseous atoms and molecules.

 

[desta41]

To get black body spectrum, you need a condensed arrangement of atoms so that transitions are 'available' amongst all the energy bands. This stuff is way beyond the elementary behaviour of idealised gaseous atoms and molecules.

When it comes to all solids, I've seen things as a collective: condensed atoms and molecules (a lattice). For liquids and very dense gases: relatively condensed atoms and molecules (without a lattice). And dilute gases: isolated atoms and molecules.

Also, from what I've been studying as of late, the correct definition for vibration of condensed atoms and molecules, in a solid, would be 'vibrational modes' (involving phonons) vs. vibrational transitions (i.e. the category of) and that it's these vibrational modes that are responsible for blackbody radiation. Would this be a more accurate way of describing things (vs. the wording I'd been using prior to now)?

Another thing. I've seen a number of sources state that blackbody radiation also occurs from liquids and very dense gases, despite the fact that things aren't as condensed (as with solids). So, then, do liquids and very dense gases involve vibrational modes or just the categories of electronic, vibrational, and rotational? And if it's just the categories, then how could blackbody radiation be possible from liquids and very dense gases?

 

[sophiecentaur]

how could blackbody radiation be possible from liquids and very dense gases

Have you understood (i.e. could you reproduce the arguments) everything about the solid state/ I would recommend that you get totally sorted in that direction before you try to get to grips with the sort of statistics involved with liquids and gases under pressure. I suspect you may be just ticking things off a list, rather than learning stuff. Categorising things in this way doesn't get one far in the direction of 'understanding'. In the end it's the actual numbers involved that determine how things work.

 

[desta41]

Have you understood (i.e. could you reproduce the arguments) everything about the solid state/ I would recommend that you get totally sorted in that direction before you try to get to grips with the sort of statistics involved with liquids and gases under pressure. I suspect you may be just ticking things off a list, rather than learning stuff.

You know, I've seen users in various related forums ask questions that show much less study and thought put into their area of interest/concern and get treated with more respect than that which you've shown me. If you'd chosen to be more focused, in your posts, on helping me with straight-forward type answers vs. criticizing me at every turn and trying to size me up -- and making claims about me that are flat out wrong, this would have been a much more pleasant experience. But, instead, it's been a pretty demeaning one, at times, and especially in regard to my last post ('ticking things off a list, rather than leaning stuff' -- really?).

I lead an extremely busy life and am trying to take in as much knowledge as I can, in the little spare time I have, regarding certain areas of science in which I have a very deep interest. We all go about our learning differently due to lifestyle, time constraints, etc. As I said before, the approach you've taken with me is not appreciated and very non-constructive.

One important emergent, collective property that a solid has that are not found in isolated atoms and molecules is presence of phonons. This is a vibrational modes of a solid due to the gazillion atoms and molecules that make up the solid.

Moving on, it was ZapperZ, who in an earlier post discussed the matter of vibrational modes and phonons and absorbtion/emission. It was overlooked by me, at the time, due to a number of other issues I was involved with (both related and unrelated).

I've given a lot of time to the matter over the past day, researching, and have come to see that what ZapperZ was talking about answers a lot (helped put the pieces together much better). I feel as if I've been led into the right direction and have a better perspective on the matter.

So my last question in the last paragraph of my last post, which was a very good one, by the way, didn't warrant such a response (neither did). Simply not productive.

To ZapperZ (and equally to DrClaude): Those are the kinds of answers I appreciate. Straight forward and with a great attitude. Much appreciated!

 

[sophiecentaur]

As I said before, the approach you've taken with me is not appreciated and very non-constructive.

I must admit that I have been letting myself get too ratty with you. I apologise.
However, you say that you have little time to study this stuff and it is clear that you are trying to hurry too fast through the topic. (A lot of time"today" is hardly a big effort, is it?) it?)If you really don't have much time then I think you should accept that you will make slow progress. Nothing at all wrong with that. It's much more worth while to get a good grounding of basic stuff than to have a whistle stop tour through stuff that you are not in a position to grasp. You need to respect the subject more. It is not easy - why else do you think it took so long for many talented people to get the Science to where it is today? I am being very realistic here, you know.

 

[Andrew Mason]

If I take a bunch of protons and jiggle it up and down, I can generate light.

ANY accelerated charge will create EM radiation.

Zz.

Is a falling proton (under gravity) accelerating?

AM

 

[sophiecentaur]

Is a falling proton (under gravity) accelerating?

AM

Why not? The energy of the photon would be pretty low, of course and you would be hard put to actually detect it.

 

[rootone]

Is a falling proton (under gravity) accelerating?

AM

I think you probably meant 'photon' not 'proton'.
If that's the case then no, photons do not accelerate, they travel only at the speed of light.(They can gain energy by changing frequency though)
If you did mean protons, you are talking of hydrogen nucleii, they can be accelerated by gravity and also by electromagnetic fields.

 

[desta41]

A lot of time"today" is hardly a big effort, is it?) it?

You're killing me here :-/

Had just asked a question, that's all.

But, I can understand your viewpoint and what you're saying..

 

[sophiecentaur]

You're killing me here :-/

Had just asked a question, that's all.

But, I can understand your viewpoint and what you're saying..

But did you read the multitude of answers that told you the same thing? You just didn't seem to be taking it on board. QM is not just a five minute job. Go at it at a steady pace and you can be more certain of what you have learned. No short cuts, I'm afraid.
BTW, there is more to "Research" than finding some instant links on Google. Figuring out things on your own can be fun, you know.

 

[Andrew Mason]

I think you probably meant 'photon' not 'proton'.
If that's the case then no, photons do not accelerate, they travel only at the speed of light.(They can gain energy by changing frequency though)

No. I meant "proton".

If you did mean protons, you are talking of hydrogen nucleii, they can be accelerated by gravity and also by electromagnetic fields.

My question was in response to ZapperZ's post in which he stated ANY accelerating charge will create EM radiation. If falling protons are accelerating and if Einstein is correct that a falling proton is equivalent to a proton at rest in an inertial frame (which does not radiate) it seems that such an accelerating charge should not create EM radiation.

This seems to be one of the few areas in classical physics that is still somewhat controversial.

AM

 

[ZapperZ]

No. I meant "proton".

My question was in response to ZapperZ's post in which he stated ANY accelerating charge will create EM radiation. If falling protons are accelerating and if Einstein is correct that a falling proton is equivalent to a proton at rest in an inertial frame (which does not radiate) it seems that such an accelerating charge should not create EM radiation.

This seems to be one of the few areas in classical physics that is still somewhat controversial.

AM

I really didn't want to dive into that can of worms, simply because the OP has more basic, fundamental misunderstanding of simpler things (after all, I don't go after people every single time when they say that one can't get photoelectrons in a photoelectric effect with photons below the work function). There have been many papers addressing this very issue (is it still "controversial"?). The paper by Boulware is one I often read (D.G. Boulware, Annals of Physics, v.124, p.169 (1980)).

This should be in a separate thread if people still want to carry on with it.

Zz.

 

[desta41]

I really didn't want to dive into that can of worms, simply because the OP has more basic, fundamental misunderstanding of simpler things

I was referring to the whole, entire collective of an object (the system) and blackbody radiation (I made it very clear a number of posts back that I wasn't talking about an isolated molecule). Unfortunately, I've been misinterpreted throughout the latter half of this thread and portrayed as the one having a misunderstanding regarding that issue.

I know a solid object has an exponential amount of molecules and atoms all packed together (I suppose I'll be smacked down for saying that, as well, by a certain someone).

It's really a shame. I put in a lot of effort (in the little free time I have) when it comes to studying and get put through the ringer for asking a few questions. And then, when apologized to for the 'ratty' treatment, I get bizarrely criticized again in the next breath. And, a lot of this has been due to someone thinking I've been referring to an isolated molecule, all along, when I haven't.

 

[sophiecentaur]

put through the ringer for asking a few questions.

Not for asking questions but for ignoring the answers (not just mine but several others).
It is of no concern to me that you have very little study time but is does concern me that you would assume that it only requires a bit of time and effort to get to know this subject well. It does require a lot (and I mean a lot) of time (and a good programme of study) to get into this subject and there is no short cut. That is not a criticism, it's an observation which applies to everyone except the very occasional genius.

 

[PeterDonis]

desta41, the topic you are asking about is quite complex, but you seem to want to reduce it to a simple, small number of "ways a photon can be emitted". I don't think that's a fruitful strategy.

For example, the answer to the title question of this thread, as you ask it, is simple: "No." But the reason the answer is "no" is not that, oh, there isn't just one kind of thing that can emit photons (electrons), but three or four (electrons, molecular vibrations, rotations, ...). The reason the answer to your title question is "no" is that there are lots of different kinds of things that can emit photons, and it isn't useful to try to classify them into a small number of categories. If you want to understand this subject, you will need to spend enough time to learn about the complexities. As sophiecentaur says, there is no short cut.