Editing George Gamow (section)

== Radioactive decay ==
In the early 20th century, radioactive materials were known to have characteristic exponential decay rates, or half-lives. At the same time, radiation emissions were known to have certain characteristic energies. By 1928, Gamow in Göttingen had solved the theory of the [[alpha decay]] of a nucleus via [[Quantum tunnelling|tunnelling]], with mathematical help from [[Nikolai Kochin]].<ref>{{Cite web |url=http://www.aip.org/history/ohilist/4325.html |title=Interview with George Gamow by Charles Weiner at Gamow's home in Boulder, Colorado, April 25, 1968. (In the transcript Kochin is spelled Kotshchin.) |access-date=April 11, 2008 |archive-date=November 24, 2009 |archive-url=https://web.archive.org/web/20091124151512/http://www.aip.org/history/ohilist/4325.html |url-status=dead }}</ref><ref>''Z. Physik'' '''5'''1, 204 (1928) G. Gamow, "Zur Quantentheorie des Atomkernes".</ref> The problem was also solved independently by [[Ronald Wilfred Gurney|Ronald W. Gurney]] and [[Edward Condon|Edward U. Condon]].<ref>R. W. Gurney and E. U. Condon, "Quantum Mechanics and Radioactive Disintegration" ''Nature'' '''122''', 439 (1928); ''Phys. Rev.'' 33, 127 (1929).</ref><ref name = "Nuc&RadChem">{{Cite book |author1=Friedlander, Gerhart |author2=Kennedy, Joseph E |author3=Miller, Julian Malcolm | title=Nuclear and Radiochemistry | edition=2nd | date=1964 | publisher=John Wiley & Sons | location=New York, London, Sydney | isbn=978-0-471-86255-0 | pages=225–7}}</ref> Gurney and Condon did not, however, achieve the quantitative results achieved by Gamow.

Classically, the particle is confined to the nucleus because of the high energy requirement to escape the very strong nuclear [[potential well]]. Also classically, it takes an enormous amount of energy to pull apart the nucleus, an event that would not occur spontaneously. In [[quantum mechanics]], however, there is a probability the particle can "tunnel through" the wall of the potential well and escape. Gamow solved a model potential for the nucleus and derived from first principles a relationship between the [[half-life]] of the alpha-decay event process and the energy of the emission, which had been previously discovered empirically and was known as the [[Geiger–Nuttall law]].<ref>[http://www.phy.uct.ac.za/courses/phy300w/np/ch1/node38.html Gamow's derivation of this law] {{webarchive |url=https://web.archive.org/web/20090224200050/http://www.phy.uct.ac.za/courses/phy300w/np/ch1/node38.html |date=February 24, 2009 }}.</ref> Some years later, the name [[Gamow factor]] or Gamow–Sommerfeld factor was applied to the probability of incoming nuclear particles tunnelling through the electrostatic [[Coulomb barrier]] and undergoing nuclear reactions.