The discussion centers on the mechanisms by which atoms absorb or reflect photons, exploring the conditions under which these processes occur. It touches on concepts from quantum mechanics, energy conservation, and the behavior of complex systems like blackbodies, as well as historical context regarding photon reflection in crystals.
Participants express varying views on the mechanisms of photon absorption and reflection, with no consensus reached on the specifics of how these processes occur at the atomic level.
The discussion includes assumptions about atomic behavior and the nature of blackbodies that may not be fully explored, as well as the complexity involved in the reflection of photons by ensembles of atoms.
orange said:How do an atom "know" when to absorb a photon, and when not to? It seems like an atom absorbs all photons that either has energy that corresponds to the difference between two energylevels, or has any type of energy at all in which case the photon energy helps speed up the atoms oscillations. And, in some cases, it reflects the photons. I'm really confused. Why are some photons reflected?
selfAdjoint said:Energy has to be conserved, exactly. So the atom can only aborb a photon of a given energy if it is capable of "internalizing" that energy by passing to a higher energy state. Since quantum reality only allows it to do that for certain energies, it can only absorb photons of those energies.
jtbell said:A blackbody is not a single atom with a relatively small number of energy states, but a complex system of bazillions of atoms.
Gokul43201 said:Also, photons are not reflected by individual atoms, but by a large ensemble of them.
orange said:So an ideal blackbody is a collection of atoms which together are able to absorb photons of all wavelengths since it is made of such a variety of elements?
Photon-reflection in a crystal were used to examine x-rays in 1912 by W.L. Bragg. How do you mean reflection is done by a group of atoms, instead of a single atom?