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How heat energy creats photon and how it jump to other atoms?

  1. Jun 10, 2012 #1
    Hi Friends,
    I am not expert in atomic science but very interested. I have few questions.

    I hope some one may help me to understand better.

    1. Light (photon) appears when electron jump from one level to another level due to heat energy.
    1a). Is the heat affects only outer level electrons only or inner level electrons too?
    1b). If outer only level affects, then how many electrons affected, are all the electrons in outer level or one?

    2. Photon absorb by proton or space and convert into heat energy and kick out from atom and it move to another atom
    2a). Is the heat energy jump to adjacent atom or skip few and jump to another atom. Lets say, first heat affect atom1 and heat jump from atom1 to atom2 or skip atom2,atom3,atom4 and jump directly to atom5

    3. Our living place mostly filled with Oxygen (Oxygen atom) so the heat might affect all its electrons and jump to another oxygen atom.
    What kinds of atoms are filled in vacuum space and how the heat energy affects them?

    Thanks in advance
     
  2. jcsd
  3. Jun 10, 2012 #2
    No, not heat energy. This happens if the electrons are "excited" for some reason, usually when a photon hits them.

    Pretty much everything else is at least partially invalidated. Heat's a measure of the average kinetic energy of particles in an object, if I remember correctly, it doesn't exist at the atomic scale.
     
  4. Jun 10, 2012 #3

    Simon Bridge

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    It can since electrons can be thermally excited. You get fermi gas models for electrons in a solid etc etc. But the picture of how heat and photons work is a bit garbled fersure.

    So. @manimaran: welcome to PF...
    The photon is released when the atom loses energy, not when it is excited.
    The distinction is meaningless since the electrons are all identical. However, thermal interactions are seldom energetic enough to excite lower energy electrons.
    depends on the mechanism for the interaction - it will be at most one electron per photon.

    Pretty much all interactions on this scale are electromagnetic. Heat propagates through large gaps by infrared radiation (photons) and inter-molecular interactions that we'd think of as collisions are directly from the EM fields of the electron clouds (photons again). These are usually complex involving many electrons and photons together but taken one at a time you get a photon exciting an atom and then the atom de-exciting ... what you are thinking of, or electrons recoiling against the nucleus giving it a nudge and so changing the atom's velocity.

    I don't know what you are thinking of by "photon absorb by space" - it makes no sense as written. When a photon is absorbed by a nuclear proton it can be excited to another bound state in the nucleus or to "continuum" eg. ejected. That's not "heat energy" it is normal kinetic energy you are thinking of. Heat is an averaging effect when we consider lots of particles in aggregate. When all the particles that make up an object are moving in different directions then it clearly has kinetic energy but the object a a whole isn't going anywhere: that's heat.

    No idea what you are imagining here - perhaps atoms in a solid?

    When the proton is ejected, it's atom recoils in a random direction against the lattice which shakes it up. Similarly when the proton gets absorbed into another nucleus the new atom recoils in turn. It is the random motion that is the heat. Though I should point out that these nuclear reactions are usually more energetic and the protons normally just leave the solid. (I'd imagine a solid hot enough that protons can be thermally ejected would just vaporize.)

    There is no special reason to expect ejected nucleons to get captured by another random nucleus and I'd expect low-energy protons to actually be repelled by the (positively charged) nuclei.

    There is no special reason why the ejected nucleon should go immediately to the adjacent atom though the further away an atom the less likely it will capture the proton ... the details depend on the specifics of the interaction and the composition and geometry of the solid.

    This is incorrect - the most common gas in the Earth's atmosphere is Nitrogen and the most common element in the Earth's biosphere, iirc, is Carbon. But we can continue since the commonness of oxygen makes no difference to your question:
    Nope ... that would require quite a lot of energy - this much heat would render all the gas as a plasma and the electrons will be unable to join up with other atoms at all. Also remember that un-ionized oxygen is, by definition, neutrally charged ... so there is no reason for so many electrons to be attracted there in the first place. Should you be able to engineer an oxygen nucleus with no electrons at all, the freed electrons will just fly right back where they come from.

    You could, presumably, engineer a situation where you release 16 electrons into a tank full of room temperature O₂ ... in which case you'd end up with a lot of negatively ionized oxygen - one or two extra electrons per atom iirc.

    The most common atom in space is Hydrogen, light from thermal excitations from hydrogen are observed in gas clouds in space.

    I get the suspicion you are thinking of a particular example and when you write your questions you are trying to generalize from that example.

    In general - heat is the energy an object has by virtue of the random motion of it's component parts. The motion may be just randomized translation or it may be vibrational or rotational.

    Heat can be moved around by three main mechanisms - conduction, radiation, and convection.
    Convection is the physical movement of particles, radiation is where particles de-excite and emit photons which are captured by other particles some distance away, conduction occurs in solids because the random motion is opposed by the lattice interactions which try to keep atoms in place. The lattice interactions are EM in nature and so are mediated by photons too. A characteristic of convective heat transfer is inter-particle collisions.
    That should help you think about heat and light more effectively... and I'm sure the others will point out holes in this somewhat simplistic model ;)
     
    Last edited: Jun 10, 2012
  5. Jun 11, 2012 #4
    Here is a little language hint. The word "heat" is often ambiguous. "Heat" has a specific meaning only in the field of thermodynamics. The word "heat" has no specific meaning when applied to individual atoms or photons. Since you are talking about single atoms here, you should not be asking in terms of "heat". Physicists analyze "heat" using the statistics involving many atoms, not just one.
    There is no specific type of energy referred to as "heat energy." The phrase "heat energy" refers specifically to the energy that is "carried" by entropy. It usually refers to the energy carried by heat conduction. It does not refer to energy absorbed by single atoms.
    "Heat energy" can come in several different forms. "Heat energy" can be carried by electromagnetic radiation, compressive waves in matter, transverse waves in matter, or electrical current. "Heat energy" can be light, infrared radiation, ultraviolet radiation, xrays, gamma rays, audible sound, and ultrasound. One should not discuss "heat" separate from thermodynamics.
    It seems reasonable to assume that you meant "light", not "heat". Therefore, I hypothesize that what you mean by "heat" is a photon. To answer your questions better, I will substitute the word "photon" for "heat". Now, "heat" is not always in the form of photons.
    What determines which electrons "jump" depends on the energy of the photon and the occupancy of each electronic level. In order to absorb a photon, there has to be one electronic level that contains and electron and another electronic level that doesn't contain an electron. The difference in energy between the two levels has to be about the same as the energy of the photon.
    The "inner" level electrons are all filled. However, an electron can't move from one inner level to another inner level because all the inner levels are filled. One can only jump from an inner level that is filled to an outer level that is not filled with electrons.
    One has to have an empty electronic level for an electron to jump into. Otherwise, the electron can't do the jump.
     
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