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I just want to know, how can we explain the phenomena of : 'absorption of light' based on the wave aspect of light ( light is an electromagnetic wave). In fact, light has an electromagnetic field, so it has an electric field which interact with atoms's electrons, I think at this point, something might be happened and it lead to the absorption phenomena, but I don't know what is it .

Thanks .

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  • $\begingroup$ Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. $\endgroup$
    – Community Bot
    Commented Jul 9, 2022 at 22:56
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    $\begingroup$ The study of the interaction of light with matter is what gave birth to the field of Quantum Mechanics, and it really cannot be properly explained apart from QM. The electromagnetic wave of classical Maxwellian theory is an approximation, valid to describe mainly the "bulk" behavior of light. $\endgroup$
    – RC_23
    Commented Jul 9, 2022 at 23:50
  • $\begingroup$ You can crudely explain it by saying that EM waves make electrons flow back and forth near the surface of a metal or semiconductor. These have electrical resistance. This converts energy into heat. $\endgroup$
    – mmesser314
    Commented Jul 10, 2022 at 2:03
  • $\begingroup$ Although within the realm of classical electrodynamics, the transmission and reception of electromagnetic waves by a metallic antenna is a kind of photon emission and absorption. $\endgroup$
    – HEMMI
    Commented Jul 10, 2022 at 6:16
  • $\begingroup$ Emmited wave is in antiphase with the incident wave, destructive interference "cancels" this wave out, leading to less energy stored in the EM field. $\endgroup$
    – jensen paull
    Commented Jul 11, 2022 at 6:01

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Every light absorption has a preceding light emission. Electrons emit photons after an excitation. And that is where we should start.

These electrons are elementary electric charges and are, last but not least, elementary magnets. To the photons they bequeath both the electric and the magnetic field. And they do so in perfect harmony; photons have very different energy contents, but the ratio of the electric to the magnetic field is always a constant.

During absorption, however, the photons have almost no chance of hitting an electron that is in exactly the same excited state as the emitting electron. In addition to the electron being raised to a higher energy level in the atom, there is often re-emission of infrared photons and excitations within the atomic compound.

In fact, light has an electromagnetic field, so it has an electric field which interacts with atoms's electrons.

More than that. A photon interacts with both its electric and magnetic field with the material it hits. The best example is the polarised photons that emerge from an antenna rod. If these photons hit a straight antenna rod, we speak of an electrical antenna, but if they hit a circular antenna, we speak of a magnetic antenna.

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  • $\begingroup$ I think that OP is asking how can we reconcile for example absorption lines and the supposed "particle" behaviour (defined photon energy) with the wave aspect of EM. How can we explain absorption lines via wave theory? $\endgroup$
    – José Andrade
    Commented Jul 20, 2022 at 0:45

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