You are correct that an electron itself does not emit a photon in isolation. The emission of a photon typically occurs when an electron undergoes a transition from a higher energy state to a lower energy state within an atom or a material. This process is known as an electronic transition or electron transition.
In an atom, electrons occupy discrete energy levels or orbitals. These energy levels are quantized, meaning they can only have specific values. When an electron transitions from a higher energy level to a lower energy level, it releases the excess energy in the form of a photon. The energy of the photon emitted corresponds to the energy difference between the initial and final states of the electron.
The emission of a photon can occur through several mechanisms, such as spontaneous emission, stimulated emission, or absorption and subsequent re-emission. Spontaneous emission happens naturally when an excited electron decays to a lower energy state without any external influence. Stimulated emission, on the other hand, occurs when an incident photon interacts with an already excited electron, causing it to emit an identical photon. This process is the basis of stimulated emission in lasers.
It's important to note that while the electron itself does not emit a photon in isolation, it is involved in the process of photon emission or absorption due to its interaction with the electromagnetic field. Electrons play a crucial role in the generation, absorption, and transmission of photons in various physical phenomena.