Absorption, Photon

Photon absorption refers to the process by which an atom or molecule absorbs a photon and makes a transition to a higher energy level. This concept is at the heart of quantum physics and has a wide range of applications in various fields, including chemistry, biology, and materials science. (Please note that this process is intimately related to phton emission).

In the realm of quantum physics, photons are considered to be particles of light, and the absorption of these particles leads to a change in the energy state of an atom or molecule. This change in energy is related to the frequency of the absorbed photon and is described by Planck’s equation. This equation is written as:

E = hf = h \nu

where:

  • h is Planck’s constant: (h=6.62607015 \times 10^{-34} \text{J} \cdot \text{s} which is equivalent to = 4.135667696 \times 10^{-15} \text{eV} \cdot \text{s}) and
  • f is frequency, measured in Hertz, sometimes written as the Greek letter \nu.

When a photon is absorbed, it is converted into kinetic energy and excites an electron within the atom or molecule to a higher energy level. Similarly, that electron can then de-excite into a lower energy level, thus emitting a photon in the process. The process of absorption is illustrated in the figure below. 

Photon absorption is depicted as the incoming photon on the left is absorbed by the electron which kicks it up into a higher energy level.
Photon Absorption. For a higher quality version of this graphic, please follow the link to my Google Drive and download from there.

Photon absorption plays a crucial role in many natural processes, such as photosynthesis in plants, and it is also used in various technological applications, such as photovoltaics and fluorescent lighting. Additionally, understanding the principles of photon absorption is essential for the development of new technologies, such as quantum computing and quantum communication, where the control and manipulation of photons is crucial.

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  1. […] and molecules can absorb or emit electromagnetic radiation by transitioning between different energy levels. The energy of […]

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