What is happening when photon stricks a proton(hydrogen nucleus)/neutron or nucleus of any real atom ?
Depends on the wavelength or frequency of the photon. If it is very energetic (a gamma ray) it may excite the proton to a higher energy level in the nucleus. If it is a lower energy photon then nothing happens (I think!).
Thanks. Actually I'm thinking about low energy photon, because efficiency of full internal reflection is 99.999%. So incident(high intensity) photons must strick proton/neutron(nucleus). But I don't understand about "nothing happens". Would you please explain about it !
Reflection does not imply that photons strike atomic nuclei. At most energies (frequencies), photons interact with the electrons in matter, not the nuclei. This is because electrons are (a) charged entities, which are therefore affected by the electric field of the photon and (b) have very low mass, so they respond much more readily than massive charged particles such as protons. Phenomena such as refraction, reflection, absorption and emission of light are all to do with the electrons in a substance. Only at gamma ray energies is is possible for photons to move heavy protons from one state to another.
Please Register or Log in to view the hidden image! When the ring hits and obstacle (a single atom), we will notice a change in the smoke ring only if the obstacle is of a comparable size. (( I found an answer from google but you(exchemist) made it easy to me)) Answer:......I noticed that Frank Heile follows this question, but since he didn't answered, I assume that he waits for somebody else to answer, and he will correct/complete him afterwards Please Register or Log in to view the hidden image! I also have my doubts that the question is sincere, because Google and WIkipedia can respond it so much faster and better. But I still feel the need to answer the question, from a strict layman perspective, as an introduction to Frank's later answer Please Register or Log in to view the hidden image! It is just logical that the photon must interact with the nucleus, since the nucleus is matter and the photon, a boson, interacts with fermions (matter) found in the nucleus. The question is: under which circumstances will it interract? I'll try to keep things laymanish intuitive at the expense of precision: Low energy photons have a long wavelength. Imagine them as smoke rings propagating trough space (Frank, please allow me the comparison just for the sake of visualisation!). The higher the photon energy, the smaller and "denser" the ring. The vortex rotates faster when the ring gets smaller, so it has more energy. But they all propagate at the same speed. An atom is small. Visible light has a "ring diameter" much bigger than the atom radius, so you will not notice a change in a "smoke ring" hitting a much smaller "dust particle". If there is a lot of "dust", the smoke rings will just become a little bit slower, but their radius won't change (analogy for light propagation in a gas). Now let's extend the analogy to the atom. The electrons orbitting around the nucleus are not isolated, like the Earth around the Sun, because they "rotate" very fast. So their orbit "blurs" and they are themselves "smoke rings" (or other forms of "smoke") around the nucleus. If the light "smoke ring" is much denser and smaller, and the size is comparable with electron shell "blur" (X-Ray), the two smoke rings might interract. Here the magical quantum physics comes into play. The "smoke rings" will behave a little bit like balls which hit each other. There are two cases, 1. They hit elastically, and just change each other's direction, this is called Thomson scattering (wikipedia) 2. Their radius matches so good that the light "smoke ring" is absorbed in the electron "smoke ring", which gets bigger (in the context of the electron, bigger means it has more energy). This effect is used in lasers and spectrometry. Each atom has his own absorbtion frequencies. We have one more case, when the electron is free (not orbiting around a nucleus). If the photon "hits" a free electron inelastically, they might get mixed and separe again, but with different "diameters". A part of the photon's momentum (and energy) is kept by the electron. This is called the Compton scattering also explains it very well. Now, back to your question, using this flawed analogy: You can imagine that, for much smaller and "denser" "smoke rings", something will happend when they hit an nucleus. The nucleus is very small compared to the size of the atom, (how the heck can I insert a link here?) and very heavy. Since Einstein, E=mc², so the high nucleus mass corresponds to a high energy. In terms of "smoke", the layman's analogy here would be a very complicatedly "knot" of entangled structures. So you need also a "hard" photon smoke ring, means one with a high energy (small diameter). When this very hard "smoke ring" hits the nucleus, there are the same possibilities as before: 1. it hits the nucleus elastically, the photon gets deflected (scattered) 2. it hits the nucleus inelastically: now the things get complicated. Whan can happen? The "knot" structure of the nucleus is broken, some smaller "knots" or "rings" of "smoke" (energy/mass) will be displaced. But whatever happens, the conservation laws for energy and momentum apply. The lowest level of energy where we can expect something interresting to happen (the photons energy "break" the "knot") is the energy mass of 2 electrons, because the electron is the lightest stable particle. Why two of them? Because the charge must be conserved, and there is an electron with a positive charge which might emerge (an anti-electron,a positron). Wikipedia says: "The photon must have enough energy to create the mass of an electron plus a positron. The mass of an electron is 9.11 × 10−31 kg, the same as a positron. Without a nucleus to absorb momentum, a photon decaying into electron-positron pair (or other pairs for that matter) can never conserve energy and momentum simultaneously" Can the incoming photon break the nucleus and induce fission? I assume yes, for very high energies (there is no upper bound for the photon energy) But I must ask Frank Heile here, this is too much for me, the layman. The much more authoritative, complete info can be found on wikipedia: Pair production Written Mar 2, 2013
Sorry Ajanta I'm lost. What is all this stuff? Is it your thoughts, or are you quoting someone? If so who, and can you indicate which parts are quotes from this person by using italics or quotation marks or something? And who is Frank Heile?
I'm in a playful mood so will upstage ajanta and give you some links: https://www.quora.com/profile/Frank-Heile https://sites.google.com/site/fbh1949/
Sir, I found it and a little bit about Frank Heile from the link... https://www.quora.com/Do-photons-interact-with-the-nucleus
Ah I see. To be honest I found it very unclear. I didn't find the smoke ring analogy for photons at all helpful. The standard picture - of mutually perpendicular, oscillating electric and magnetic fields - is nothing at all like it, so far as I can see.
Thank you for this link to Frank-Heile's presentation, which is only about 40 minutes long, with 8o minutes or so his responce to quetions. All of his points in frist 20 minutes or so are 100% in agreement with POV expressed here: http://www.sciforums.com/threads/is...fe-is-it-an-illusion.49127/page-4#post-905778, buy what he calls the LC, I called the "Real Time Simulation" - RTS Model. For example, we both agree that the "explosion" of small part of humanity out of Africa about 50Kyears ago was due to the development of the LC or the RTS. In additions to new and capabable language, he speaks of, I add that the RTS gave a real time (instead perception with slight neural delays) understanding of the world, that made ducking a thrown rock or spear much more possible.) I said this in the link given above: "the “Out of Africa” mystery, (Why one branch of hominoids, expanded and dominated all others approximately 50,000 years ago.), which is often assumed to be related to the acquisition of “autonomous language” (no gestures required - hands free and education facilitated), might better be explained by the development of the real-time simulation of the environment." That link is extracted ideas for my publication back in 1994 (first ref. given in the link.) I will try to establish contact with Frank-Heile as we are incomplete agreement, except I add the RTS to his LC only.
I consider biology a sub division of physics. I. e. the natural laws control all chemical reactions, although just like in other parts of physics, how is not fully understood. An important question in both physics as a whole and its biology subdivision, is: Are humans just very complex bio-mechanical machines? For a long time, I thought the answer to that question was: Yes. Although Frank-Heile and I agree that most of the brain's activity is not conscious and is massively parallel processing, which he calls the PC brain, we also agree that a small part, which we are conscious of, is serial processing and makes an internal representation of the sensed environment, which can be expressed in language, and is self representative too. He calls that serial part the LC (and I call it the RTS, as I think that representation of the sensed environment is corrected for neural transmission delays, when possible). Both of us agree this serial activity creates the "agent" that we all know we are. If that agent has genuine free will, instead of just the illusion of it, there is usually an implied violation of physic - the natural laws which govern the discharge of every nerve in the body would void genuine free will. I said "usually" as I detail in the RTS link given that need not be the case, if the "agent" is part of a simulation (the S of RTS). Simulations do not necessarily conform to the natural laws. Thus, if the RTS view, with the agent as part of it is correct, then genuine free will is NOT necessarily a violation of the natural laws. If the agent, which we all consider ourselve to be, can violate the natural laws, not be controlled by neurochemistry, then that is definitely of interest to physics. I had to skim Frank-Heile's talk (due to time shortage) so am not sure whether or not his LC brain activity is deterministically controlled by neurochemistry. I. e. free will is only an illusion for him. I hope this suggests why knowing how physics (neurochemisty, nerve discharges) acts on behavior is part of physic and discussed by Frank-Heile and me in the RTS link given earlier. - - - - - - BTW, I agree with your post 9 comments - I think the "smoke ring" model of the photon is worse than useless.
This is totally irrelevant to the subject of this thread, which is about the interaction between light and matter.
I agree; but you asked how was my post (and that of Frank-Heile) related to physics, not the thread. I appeciated the F-H reference (in the otherwise useless smoke ring post) and the Q-reeus post 7 video by F-H. You will need to ask them why there are here. I just continued their detour. BTW The photon need not be destroyed when it interacts with matter There is the Compton effect.
OK, glad you found it interesting, but I will admit it was just a link grab to anything on Heile and not on topic.
Yes it's an electric field whose value changes from +ve to -ve and back as the wave passes. Look at the diagram here for example: https://www.single-molecule.nl/notes/light-waves-and-photons/ This also shows that there is a magnetic field as well, at right angles to the electric field.
And the magnetic field(of photon) whose value change also. So photon is not affected by magnetic field(of magnet) and electric field ! Thanks.
Well actually the electron can be affected by the magnetic field as well. Recall that a moving charge in a magnetic field experiences a force. But the primary mechanism by which photons interact with electrons is via their electric field.
