So I have some questions regarding photons, heat, energy and chemical bond formation.
Every body that has a temperature above absolute zero emits electromagnetic radiation in form of black body radiation. That means when there is a temperature above absolute zero there is also radiation. I feel that it is naturally to then assume that the random movement of the atoms or molecules comes from the the radiation within the body. This would also be compatible with the fact that the Maxwell-Boltzmann distribution of the velocity distribution in a gas looks similar to the Blackbody radiation intensity distribution. For example if you remove the amount of radiation caused by simulated emission in a Blackbody radiation distribution you are left with the radiation caused by spontaneous emission. This distribution of the radiation intensity caused by spontaneous emission is basically almost the same kind of distribution as the Maxwell-Boltzmann distribution of the velocities of the molecules in a gas. Then one can see that there is a correlation between the velocities of molecules in a gas and the intensities of the different frequencies that are emitted from the body in form of black body radiation. So my question is do the random velocities(momenta) of molecules in a gas above absolute zero have their origin in radiation (photons)?
I have been told that the momenta of molecules and the photons that they emit and absorb are pretty different phenomenas. But I don’t understand, why this would be the case. Since photons carry momenta and when a molecule absorbs that photon, the molecule will gain momentum from that photon. Later on when the same molecule spontaneously emit the absorbed photon it will lose its momentum gained from that photon. But I have been told the this is the wrong way of thinking and that one can have a molecule standing completely still but still being in an electronically exited state. I can’t see this happening only maybe temporarily in some crystal where the absorbed photon is forwarded through the crystal lattice, but of course that is another scenario.
Another thing that I wonder is regarding the release of energy after the formation of chemical bonds. So when to atoms or molecules for a new molecule in form of a chemical bond energy is released. I have read that this energy that is released is mostly in form of heat and in some cases light. In the textbook I read this they used the words “heat” and “light”. So I didn’t get out of this book if the actually referred to thermal radiation or “just heat”. Anyways I would argue that electromagnetic radiation has to always be given of when a more stable chemical bond forms that releases energy and this released energy has to “originally” at the moment of bond formation be in the form of electromagnetic radiation. Am I right about this?
I would say that my following thought experiment would prove my point I made above: Let’s say we but two reactants in an isolated system, these reactants would have a very low temperature at the moment they are put in an isolated system. After the reactions and the new chemical bonds have been formed this isolated system will have an higher temperature and also have more Blackbody radiation emitted from it. And this radiation has to have come from somewhere right? And I would say that is from the released energy(as electromagnetic energy) when the more stable bonds are formed.
One more trying I have been wondering about is vibrationally or rotationally “excited states” in molecules. Of course the higher the temperature the more the molecules vibrate. And I would argue that this vibration has to come from the Blackbody photons within the system, since the Blackbody radiation increases as temperature increases and vice versa. That means that these vibrationally and rotationally “excited states” of molecules has to come from photons. But I feel that many textbooks treat vibrationally and rotationally “excited states” as if the were not really working in a similar fashion to how electronically excited states work, which emit electromagnetic radiation when the electron goes to a lower energy level. Do the vibrationally and rotationally “excited states” also do this, I mean emit photons when they go from a higher energy level to a lower, maybe just in most cases in the far infrared spectrum of electromagnetic radiation and that is why textbook refer to it as “heat”?
I hope you get my questions. The main thing that I propose is, whether the “origin” of heat originally lies in photons momenta and their spontaneous emissions, which by the random direction of the photons emissions also would be the cause of Brownian motion being a random walk.
And the last question in case I am right would be what happens during collisions of molecules? Can the photon of one molecule “be transferred” to that of the other molecule in case there is a “equivalent” energy level. In case two different molecules with different energy levels collide what happens then regarding the momentum of the molecule and the photons “within” these molecules/the excited energy levels?
