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Nuclear reactions. Naturally occurring nuclear reactions powered by radioactive decay give rise to so-called nucleogenic nuclides. This process happens when an energetic particle from radioactive decay, often an alpha particle, reacts with a nucleus of another atom to change the nucleus into another nuclide.
Synthesis of nucleosides involves the coupling of a nucleophilic, heterocyclic base with an electrophilic sugar. The silyl-Hilbert-Johnson (or Vorbrüggen) reaction, which employs silylated heterocyclic bases and electrophilic sugar derivatives in the presence of a Lewis acid, is the most common method for forming nucleosides in this manner.
In contrast, the radioactive nuclide beryllium-7 falls into the same light element range but has a half-life too short for it to have been formed before the formation of the Solar System, so that it cannot be a primordial nuclide. Since the cosmic ray spallation route is the most likely source of beryllium-7 in the environment, that isotope is ...
More lithium, beryllium and boron were produced later, in a natural nuclear reaction, cosmic ray spallation. Stellar nucleosynthesis is responsible for all of the other elements occurring naturally in the universe as stable isotopes and primordial nuclide, from carbon to uranium. These occurred after the Big Bang, during star formation.
In nuclear astrophysics, the rapid neutron-capture process, also known as the r-process, is a set of nuclear reactions that is responsible for the creation of approximately half of the atomic nuclei heavier than iron, the "heavy elements", with the other half produced by the p-process and s-process.
The radioactive decay can produce a stable nuclide or will sometimes produce a new unstable radionuclide which may undergo further decay. Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay.
A series of these reactions produces stable isotopes by moving along the valley of beta-decay stable isobars in the table of nuclides. A range of elements and isotopes can be produced by the s-process, because of the intervention of alpha decay steps along the reaction chain. The relative abundances of elements and isotopes produced depends on ...
The following apply for the nuclear reaction: a + b ↔ R → c. in the centre of mass frame, where a and b are the initial species about to collide, c is the final species, and R is the resonant state.