Science

longship

(40,416 posts)

10. Helium-2 is extremely unstable.

Thu Dec 17, 2015, 08:09 AM

Dec 2015

Last edited Thu Dec 17, 2015, 02:56 PM - Edit history (3)

It has negative binding energy. It immediately changes to an atom of deuterium via beta-plus decay.

The effective transformation is this:

H1 + H1 -> D2 + e+ + nu + 0.42 MeV

(Sorry, don't know how to type Greek. nu is the electron neutrino. e+ is the positron, D2 is deuterium, heavy hydrogen.)

So, no. Helium-2 is not found in nature. It is only seen in the cores of main sequence stars as part of the fusion process that generates He-4. It is only there as a step which inevitably and instantly leads to Deuterium, which subsequently fuses to He-4.

So I will stand by my posts.

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German Physicists Reach Milestone In Nuclear Fusion Energy Quest [View all] muriel_volestrangler Dec 2015 OP

One has to use deuterium. longship Dec 2015 #1

Deuterium is relatively easy to concentrate, though muriel_volestrangler Dec 2015 #2

Yup! longship Dec 2015 #3

3H, not 3He. nt thereismore Dec 2015 #4

It both works, one reaction throws away a neutron, the other reaction throws away a proton jakeXT Dec 2015 #5

Nice, thanks. nt thereismore Dec 2015 #6

Elemental helium has no neutrons. Angleae Dec 2015 #7

AFAIK, almost all helium has 2 neutrons. longship Dec 2015 #8

On earth yes. In space no. Angleae Dec 2015 #9

Helium-2 is extremely unstable. longship Dec 2015 #10

Beta decay takes care of that. Treant Dec 2015 #11