Define spontaneous emission

Answer 1

Spontaneous emission refers to the process in which an atom or molecule in an excited state transitions to a lower energy state without any external stimulus or interaction. During this process, the atom or molecule emits a photon, which carries away the excess energy. The emission occurs randomly and is not influenced by the presence of surroundings or external fields. Spontaneous emission is a fundamental phenomenon in quantum mechanics and is responsible for various phenomena such as the fluorescence of materials and the decay of excited states in atoms.