Momentum of radiation

A related problem is that the linear momentum of radiation in U(l) is defined... 

These concepts of 0(3) electrodynamics also completely resolve the problem that, in Maxwell-Heaviside electrodynamics, the energy momentum of radiation is defined through an integral over the conventional tensor and for this reason is not manifestly covariant. To make it so requires the use of special hypersurfaces as attempted, for example, by Fermi and Rohrlich [40]. The 0(3) energy momentum (78), in contrast, is generally covariant in 0(3) electrodynamics [11-20]. 

The fundamental hypothesis of the theory now presented is that the momentum of radiation is transferred to and from matter in quanta, and further, that the laws of the conservation of energy and of momentum apply to these transfers. 

We first examine the reiationship between particie dynamics and the scattering of radiation in the case where both the energy and momentum transferred between the sampie and the incident radiation are measured. Linear response theory aiiows dynamic structure factors to be written in terms of equiiibrium flucmations of the sampie. For neutron scattering from a system of identicai particies, this is [i,5,6]... 

Applied radiation chemistry has gained considerable momentum since the late sixties and early seventies, and it would be futile to describe all the progress made in a single chapter. Spinks and Woods (1990) have nicely summarized the synthetic and processing aspects of the field in the latest edition of their book. Proceedings of various international conferences on specific aspects of radiation applications have appeared sporadically in Radiation Physics and Chemistry starting from middle seventies, of which mention may be made of vol. 9 (1977), vol. 14 (1979), vol. 25 (1985), vol. 31 (1988), vol. 34 (1989), vols. 35-36 (1990), vol. 37 (1991), vol. 40 (1992), vol. 42 (1993), and vol. 46 (1995). A... 

Following Rutherford s experiments in 1911, Niels Bohr proposed in 1913 a dynamic model of the hydrogen atom that was based on certain assumptions. The first of these assumptions was that there were certain "allowed" orbits in which the electron could move without radiating electromagnetic energy. Further, these were orbits in which the angular momentum of the electron (which for a rotating object is expressed as mvr) is a multiple of h/2ir (which is also written as fi),... 

Momentum distribution function Faraday / Inhibitor Intensity of radiation... 

The purpose of the series was to accumulate scientific data, such as inside, outside and skin temperatures density, distribution and momentum of micro-meteorites, cosmic-ray intensity energy and intensity of corpuscular radiations, X-radiation, die extent of the earth s radiation belt, map the earth s magnetic field, etc Note 1 Perigee is the point in the orbit of a satellite of the earth that is nearest to the earth... 

Our understanding of the basic nature of matter is limited by Heisenberg s uncertainty principle. Stated simply, this principle implies that our measurements of the position and momentum of a particle of subatomic mass arc always in error when radiation is used to study matter. If x... 

Prompt y-ray emission competes with or follows the last stages of prompt neutron emission. These photons are emitted in times from 10 15-10 7s. Typical y-ray multiplicities of 7-10 photons/fission are observed. These photons, as indicated earlier, cany away 7.5 MeV. This y-ray yield is considerably larger than one would predict if y-ray emission followed neutron emission instead of competing with it. Because of the significant angular momentum of the fission fragments ( 7-10 h) even in spontaneous fission, photon emission can compete with neutron emission. The emitted y rays are mostly dipole radiation with some significant admixture of quadrupole radiation, due to stretched El transitions (J/= 7, — 2). 

In 1917 Einstein [18] wrote a paper on the dualistic nature of light in which he discusses emission without excitation from external causes, in other words stimulated emission and also spontaneous absorption and emission. He derives Planck s formula but also discusses the recoil of molecules when they emit photons. It is the latter discussion that Einstein regarded as the most significant aspect of the paper If a radiation bundle has the effect that a molecule struck by it absorbs or emits a quantity of energy hv in the form of radiation (ingoing radiation), then a momentum hvlc is always transferred to the molecule. For an absorption of energy, this takes place in the direction of propagation of the radiation bundle for an emission, in the opposite direction. ... 

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