Collision between photon and atom

In summary, photon absorption can be considered as both an elastic and inelastic collision, depending on the resonant conditions and decay channels of the excited electron. However, if the definition of "elastic collision" is strictly applied, then absorption is an inelastic process.
  • #1
kmarinas86
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1
Is photon absorption an elastic or inelastic collision? neither?
 
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  • #2
Under resonant conditions you can look at the absorption process as an elastic scattering event and as an inelastic one while off resonance. On resonance it also dependends on what decay channels the excited electron has.
 
  • #3
kmarinas86 said:
Is photon absorption an elastic or inelastic collision? neither?
The term "elastic collision" usually refers to a two-body scattering where each body has the same final energy in the center of mass system as its initial energy. With this definition, absorption is an inelastic process.
 
  • #4
kmarinas86 said:
Is photon absorption an elastic or inelastic collision? neither?
If the photon is "absorbed" it means that its energy is totally or partially transferred to the absorbing system, so the process it's inelastic by definition. However, if another photon of the same energy is emitted immediately after the absorption, the overall process can be considered as elastic.
 

1. What happens when a photon collides with an atom?

When a photon collides with an atom, several things can happen. The photon may be absorbed by the atom, causing an electron to jump to a higher energy level. The photon may also be scattered, changing direction and possibly changing its energy. In some cases, the photon may pass through the atom without being absorbed or scattered.

2. How does the energy of a photon affect its collision with an atom?

The energy of a photon is directly related to the frequency or color of the light. Higher energy photons, such as ultraviolet or X-rays, are more likely to be absorbed by an atom, while lower energy photons, such as infrared or radio waves, are more likely to pass through the atom without interaction.

3. Can a photon cause an atom to change its state or behavior?

Yes, a photon can cause an atom to change its state or behavior. When a photon is absorbed by an atom, it can cause an electron to jump to a higher energy level, changing the atom's state. This can also lead to changes in the atom's behavior, such as emitting a new photon or participating in a chemical reaction.

4. How does the size of an atom affect its collision with a photon?

The size of an atom does not have a significant effect on its collision with a photon. The interaction between a photon and an atom is determined by the atom's electron configuration and the energy of the photon, rather than its size. However, larger atoms may have more electrons, increasing the chances of a photon being absorbed or scattered.

5. What are some real-world applications of collisions between photons and atoms?

Collisions between photons and atoms have many real-world applications. For example, they are used in spectroscopy to study the energy levels of atoms. They are also used in technologies such as solar cells, lasers, and medical imaging. Additionally, collisions between photons and atoms play a crucial role in the Earth's atmosphere, as they contribute to the absorption and scattering of sunlight, which affects our climate.

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