Beryllium-8

Physicists John Douglas Cockcroft and Ernest Walton performed their first experiment with their accelerator at the Cavendish Laboratory in Cambridge, in which they irradiated lithium-7 with protons.

The decay of 8Be is facilitated by the structure of the 8Be nucleus; it is highly deformed, and is believed to be a molecule-like cluster of two alpha particles that are very easily separated.

[10] A 2015 experiment by Attila Krasznahorkay et al. at the Hungarian Academy of Sciences's Institute for Nuclear Research found anomalous decays in the 17.64 and 18.15 MeV excited states of 8Be, populated by proton irradiation of 7Li.

The triple-alpha process, despite being a three-body reaction, is facilitated when 8Be production increases such that its concentration is approximately 10−8 relative to 4He;[16] this occurs when 8Be is produced faster than it decays.

[1] In 1954, Fred Hoyle thus postulated the existence of a resonance in carbon-12 within the stellar energy region of the triple-alpha process, enhancing the creation of carbon-12 despite the extremely short half-life of beryllium-8.

[19] The existence of this resonance (the Hoyle state) was confirmed experimentally shortly thereafter; its discovery has been cited in formulations of the anthropic principle and the fine-tuned Universe hypothesis.

[1] These studies suggest that the disappearance of the bottleneck[20] created by 8Be would result in a very different reaction mechanism in Big Bang nucleosynthesis and the triple-alpha process, as well as alter the abundances of heavier chemical elements.

[4] As Big Bang nucleosynthesis only occurred within a short period having the necessary conditions, it is thought that there would be no significant difference in carbon production even if 8Be were stable.