What is the phenomenon called when electrons are ejected out of atoms after absorbing a photon?

The phenomenon where electrons are ejected from atoms after absorbing a photon is known as the photoelectric effect. This process occurs when the energy of the incoming photon is sufficient to overcome the binding energy of the electron within the atom. When the photon is absorbed, its energy is transferred to the electron, providing it with enough energy to escape from the atom.

The photoelectric effect is a fundamental principle explaining various phenomena in quantum mechanics and is crucial in the working of devices like photovoltaic cells and photo detectors. It illustrates the particle-like behavior of light, where photons are considered discrete packets of energy.

While the other terms mentioned relate to different physical interactions involving photons and matter, they do not describe the ejection of electrons from atoms specifically due to photon absorption. For instance, the Compton effect refers to the scattering of photons by free electrons, where the photon transfers some of its energy to the electron but does not generally result in the direct ejection of that electron from the atom itself. Rayleigh scattering pertains to the scattering of light by particles much smaller than the wavelength of the light, without the change in energy or the ejection of electrons. Ionization is a more general term that describes the process of adding or removing electrons from an atom, but in