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To create an electron-positron pair, the total energy of the photons, in the rest frame, must be at least 2m e c 2 = 2 × 0.511 MeV = 1.022 MeV (m e is the mass of one electron and c is the speed of light in vacuum), an energy value that corresponds to soft gamma ray photons.
Photonic molecules are formed when individual (massless) photons "interact with each other so strongly that they act as though they have mass". [4] In an alternative definition (which is not equivalent), photons confined to two or more coupled optical cavities also reproduce the physics of interacting atomic energy levels , and have been termed ...
The RTE is a differential equation describing radiance (, ^,).It can be derived via conservation of energy.Briefly, the RTE states that a beam of light loses energy through divergence and extinction (including both absorption and scattering away from the beam) and gains energy from light sources in the medium and scattering directed towards the beam.
Because photons have zero rest mass, no wave function defined for a photon can have all the properties familiar from wave functions in non-relativistic quantum mechanics. [ f ] In order to avoid these difficulties, physicists employ the second-quantized theory of photons described below, quantum electrodynamics , in which photons are quantized ...
Consider a non-relativistic electron bath that is at an equilibrium temperature , i.e., , where is the electron mass. Let there be a low-frequency radiation field that satisfies the soft-photon approximation, i.e., ℏ ω ≪ m e c 2 {\displaystyle \hbar \omega \ll m_{e}c^{2}} where ω {\displaystyle \omega } is the photon frequency.
The Gibbs free energy for converting a mole of CO 2 to glucose is 114 kcal, whereas eight moles of photons of wavelength 600 nm contains 381 kcal, giving a nominal efficiency of 30%. [2] However, photosynthesis can occur with light up to wavelength 720 nm so long as there is also light at wavelengths below 680 nm to keep Photosystem II ...
Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by absorption of light or photons. It is defined as the interaction of one or more photons with one target molecule that dissociates into two fragments. [1]
This extra equation can be used as a closure relation for the truncated system of moments. Note that the first two moments have simple physical meanings. J ν {\displaystyle J_{\nu }} is the isotropic intensity at a point, and H ν {\displaystyle H_{\nu }} is the flux through that point in the z {\displaystyle z} direction.