Which of the SEMF terms account for low A binding energy?

[Flucky]

Homework Statement

Which of the semi-empirical mass formula terms accounts for a drop in stability at low A and why?

Homework Equations

B = a_vA - a_sA^{$\frac{2}{3}$} -a_cZ(Z-1)A^{$\frac{-1}{3}$} -a_a(A-2Z)²A^-1 ± a_pA^{$\frac{3}{4}$}

The Attempt at a Solution

I'm struggling getting my head around this one.

The Coulomb term will decrease the binding energy as Z increases so I've ruled that out.

The asymmetric term decreases the binding energy as N>Z (more stable when N ≈ Z) so I've ruled that out.

All the rest are only dependent on A, so I would guess that it is the first term (volume term) that is the cause of low A instability. However the volume term increases linearly with A and it's such a dramatic change when looking at the binding energy per nucleon curve.

I can't explain why it would be the volume term if it is.

Any ideas?

 

[Greg Bernhardt]

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?