Light emission happens when an electron transitions from a higher energy level to a lower energy level within an atom or molecule. When an electron absorbs energy, it moves to an excited state (a higher energy level), which is unstable. To return to a more stable state (the ground or a lower energy state), the electron releases the excess energy in the form of a photon, which is a particle of light. This process of releasing a photon is called light emission. More specifically:
- When an electron drops from an excited state back to a lower-energy state, the energy difference between these two states is emitted as a photon of light.
- The energy of the emitted photon corresponds to the energy difference between the electron's initial and final states.
- This photon emission can happen spontaneously (spontaneous emission) or be triggered by the presence of other photons (stimulated emission).
- The phenomenon underlies many natural and technological processes, including fluorescence, phosphorescence, and the operation of lasers.
So, light emission occurs when the electron de-excites by transitioning from a higher energy state to a lower energy state, releasing the energy difference as light.
