Introduction to Phosphorescence
Phosphorescence is a slowly glowing photoluminescence phenomenon. When a certain temperature substance is irradiated with incident light of a certain wavelength (usually ultraviolet or X-ray), it absorbs light energy and enters an excited state (usually having a spin multiplicity different from the ground state), then slowly de-excites and emits a ratio Outgoing light with a long wavelength of incident light (usually in the visible band). When the incident light stops, the luminescence phenomenon persists. The deexcitation process that emits phosphorescence is forbidden by the transition selection rule of quantum mechanics, so this process is very slow. The so-called "glow in the dark" materials are usually phosphorescent materials, such as night pearls.