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High-schooler alert, be patient.

If we consider a Bohr Model of an atom used for introduction to atomic physics with a nucleus in the centre and electrons "flying" around it (no waves), then how does it "look" like when light passes through (when there is no-little absorption and scattering by electrons)?

If we imagine light as particles-asteroids flying through our atom-planet, than through interactions between electric fields, electrons have to experience a force? Or if we look from the perspective of light "flying" beside an atom, does it create (almost infinitesimal) force on that atom that can propagate through that medium?

Consider light to be of a monochromatic source and an atom to be at the top of a glass medium.

Does the hoard of photons leave electrons twirling and "jiggling" around an atom with more rapid speeds?

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    $\begingroup$ What does this question have to do with sound? (in the title) $\endgroup$ Commented May 27 at 3:50
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    $\begingroup$ that can propagate through that medium? What medium are you talking about? All you have mentioned is “an atom” and light. $\endgroup$ Commented May 27 at 3:51
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    $\begingroup$ The Bohr model, as far as I know, doesn’t attempt to model the interaction of atomic electrons with electromagnetic waves. I suggest choosing a better model that does. $\endgroup$ Commented May 27 at 3:54
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    $\begingroup$ When the Sun rises and the light hits my house, the structure creaks from thermal expansion. That’s light creating sound. $\endgroup$ Commented May 27 at 3:56
  • $\begingroup$ @Allure As I try to explain, do electrons experience a force pushing on other atoms’ electrons in their vicinity, which creates a longitudinal wave? $\endgroup$ Commented May 27 at 3:59

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Yes, but not quite in the way you are thinking. The Bohr model isn't accurate and isn't a good way to think about it.

A photon is a particle of light. It carries energy and momentum. When it hits an atom, it can be absorbed. This adds energy to the atom, kicking it up to an excited state. It adds momentum to the atom, making it recoil.

It the atom is bound to a crystal lattice, the recoil can generate a wave that propagates through the lattice. This is called a phonon. It is a sound wave, though usually at a frequency way above human hearing.

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  • $\begingroup$ Thank you for your answer. This makes sense to me. Are you aware if such a “phonon” could be detected? Or would it be of too high frequency? $\endgroup$ Commented May 27 at 4:06
  • $\begingroup$ And if you could please suggest, if the photon doesn’t get absorbed by an atom, then does it leave it twirling behind it because of EM field interactions? Thank you! $\endgroup$ Commented May 27 at 4:08
  • $\begingroup$ @KyryloLyskov No. If the atom doesn't absorb the photon, then the photon has no measurable effect on the atom. $\endgroup$ Commented May 27 at 4:23
  • $\begingroup$ @KyryloLyskov look up a description of an acousto-optic modulator. You can consider the deflection of the laser beam in such a device as an indirect detection of phonons. More directly: Glue a copper foil to the front of a piezeoelectric transducer and illuminate it with a high pulse energy pulsed laser while monitoring the voltage across the transducer. You're not going to measure single phonons like this, but they are in essence the particle mediating the interaction. $\endgroup$ Commented May 27 at 14:20
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    $\begingroup$ Also note that phonons aren't "real" particles, they only exist as a collective oscillation of particles in a lattice. You can't have a phonon flying around in vacuum, unlike a photon. $\endgroup$ Commented May 27 at 14:22
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If you focus a high-powered laser pulse to a point in air, it makes a nice "snap" sound. One way to understand this is that low intensity, light only interacts with matter one photon at a time. Visible light photons interact weakly with air molecules: they don't have enough energy to excite them. But at high intensity, at the focus, two or more photons can transfer their combined energy to a molecule and ionize it. Do this to a bunch of molecules and the result is an expanding hot plasma ball, and thus a sound.

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Indeed, absorption of light by solids may be mediated by emission of phonons, i.e., sound waves in crystal.

Another related process is Mandelstam-Brillouin scatteirng, which is similar to Raman scattering, but the scattering occurs between light and sound/polarization/magnetic waves in solids, with scattered light having different energy - this is closely related to Raman scattering from atoms (in fact Mandelstam and co-workers also discovered Raman scattering, but were a few days later than Raman to publicize their results - the year was 1928.)

This does not happen for sound waves in air, since those are essentially thermodynamic, resulting from pressure changes mediated by many random collisions between atoms, while absorption of light occurs by a single atom, on much shorter time- and length-scales.

Related:
Are there phonons in air?
Is sound a classical mechanic phenomenon or is it a quantum effect?

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  • $\begingroup$ Thanks for your insights, I’ll take a look! $\endgroup$ Commented May 27 at 15:26

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