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Alpha decay as tunnelling
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Alpha particles escape the nucleus through the Coulomb barrier.
Alpha particles escape the nucleus by tunnelling through the Coulomb barrier (Gamow, 1928), explaining the huge range of half-lives (10⁻⁷ s to 10¹⁷ years) from small energy differences.
Uranium-238: 4.5 billion years.
Geiger–Nuttall law.
In more detail
Alpha decay can be explained as a particle tunnelling through the nuclear potential barrier. This explained the wide range of decay lifetimes, which depends on the barrier and energy.
Real-world uses
- Alpha emitters are used in smoke detectors and radioisotope power sources.
- Understanding decay lifetimes helps in radiometric dating.
- Physicists explain the lifetime of radioactive nuclei by treating alpha escape as tunnelling through the Coulomb barrier.
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Frequently asked questions
Why does this matter?
Classical physics could not explain why alpha particles escape nuclei at all.
Who first explained it this way?
George Gamow and others in 1928.
Why do some nuclei decay faster than others?
The height and width of the barrier, and the energy of the alpha particle, set how often it tunnels out.
Related topics in Quantum Mechanics
Finite potential well · Quantum tunnelling · Tunnelling applications · Quantum harmonic oscillator · Zero point energy · Hydrogen atom in quantum mechanics