# Binding energy and favorable reactions

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1. Jun 21, 2016

### letec

[Moderator note: Thread moved from technical section, thus no template is shown]

Hi everyone!
I'm currently learning nuclear physics and I have a question:
Watching the binding energy per nucleon curve, is the following reaction energetically favorable?
2H + 4He -> 6Li
And why?

Thanks!!!

2. Jun 21, 2016

### Staff: Mentor

Why don't you take the values from the diagram and check for yourself? Better (more accurate): Look up the binding energies (or the masses) and calculate it.

3. Jun 21, 2016

### letec

4. Jun 21, 2016

### Staff: Mentor

I moved you to the homework section.

Well, then use the diagram and check it.

5. Jun 21, 2016

### letec

That's exactly my question... The binding energy of the 4He is bigger than the B.E of the product. Is that it? or is there something more?

6. Jun 21, 2016

### Staff: Mentor

What about the binding energy of deuterium?

7. Jun 21, 2016

### letec

well it's smaller! and that is my question!

8. Jun 21, 2016

### Staff: Mentor

No, that is the homework question.

What is the combined binding energy of D+4He?

9. Jun 21, 2016

### letec

do you mean for 2H + 4He -> 6Li:
2*1 MeV + 4*7MeV = 30MeV < 6*5.3 = 31.8 therefore the reaction is energetically favorable?

10. Jun 21, 2016

### Staff: Mentor

Sure.

To conserve energy and momentum, you would need an additional photon in the final state.

11. Jun 26, 2016

### letec

Thanks for the help! :)