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Internal conversion is an atomic decay process where an excited nucleus interacts electromagnetically with one of the orbital electrons of an atom. This causes the electron to be emitted (ejected) from the atom. [1] [2] Thus, in internal conversion (often abbreviated IC), a high-energy electron is emitted from the excited atom, but not from the ...
The one-electron universe postulate, proposed by theoretical physicist John Wheeler in a telephone call to Richard Feynman in the spring of 1940, is the hypothesis that all electrons and positrons are actually manifestations of a single entity moving backwards and forwards in time. According to Feynman:
Internal conversion is a transition from a higher to a lower electronic state in a molecule or atom. [1] It is sometimes called "radiationless de-excitation", because no photons are emitted. It differs from intersystem crossing in that, while both are radiationless methods of de-excitation, the molecular spin state for internal conversion ...
The latter case occurs if the neutrinos are Majorana particles, being at the same time matter and antimatter, according to the definition given just above. [1] In a wider sense, one can use the word matter simply to refer to fermions. In this sense, matter and antimatter particles (such as an electron and a positron) are
An example is internal conversion, which results in an initial electron emission, and then often further characteristic X-rays and Auger electrons emissions, although the internal conversion process involves neither beta nor gamma decay. A neutrino is not emitted, and none of the electron(s) and photon(s) emitted originate in the nucleus, even ...
The internal conversion coefficient may be empirically determined by the following formula: = There is no valid formulation for an equivalent concept for E0 (electric monopole) nuclear transitions. There are theoretical calculations that can be used to derive internal conversion coefficients.
The theory of electron capture was first discussed by Gian-Carlo Wick in a 1934 paper, and then developed by Hideki Yukawa and others. K-electron capture was first observed by Luis Alvarez, in vanadium, 48 V, which he reported in 1937. [3] [4] [5] Alvarez went on to study electron capture in gallium (67 Ga) and other nuclides. [3] [6] [7]
A corollary of Kasha's rule is the Vavilov rule, which states that the quantum yield of luminescence is generally independent of the excitation wavelength. [4] [7] This can be understood as a consequence of the tendency – implied by Kasha's rule – for molecules in upper states to relax to the lowest excited state non-radiatively.