Radiative

Radiative is an adjective relating to radiation, the energy carried by electromagnetic waves or particles such as photons. In scientific usage, radiative describes processes that involve emission, absorption, or transmission of energy by radiation, as opposed to conductive or convective transfer.

In physics and engineering, radiative transfer describes how radiation propagates through and interacts with matter. The radiative transfer equation accounts for emission, absorption, and scattering along a path. Blackbody radiation, emissivity, and the Stefan–Boltzmann law are central concepts. Radiative heat transfer is significant at high temperatures or in vacuum and is described by view factors and surface properties.

In atomic, molecular, and optical sciences, radiative processes include spontaneous emission, fluorescence, and phosphorescence—where excited states decay by photon emission. Radiative lifetimes, transition probabilities, and selection rules govern these processes.

In astronomy and atmospheric science, radiative mechanisms determine the spectra of stars and planets. Radiative transfer models predict how light is absorbed and emitted in atmospheres; radiative forcing describes how changes in radiation balance influence climate.

The term is often used with prefixes to distinguish from non-radiative processes (e.g., radiative cooling versus convective cooling). Practical concerns include radiative properties such as emissivity, absorptivity, reflectivity, and opacity.

Radiative processes are fundamental across disciplines, from energy balance in engineering to the interpretation of astronomical observations.