= Neutron-capture excitation energy
{title2=$E^*=S_n(A+1,Z)+E_n^{\rm CM}$}
After neutron capture on $(A,Z)$, the compound nucleus is $(A+1,Z)$. With negligible incoming kinetic energy, conservation of <energy> gives $E^*=M(A,Z)+m_n-M(A+1,Z)$ in <natural units>. This is the <neutron separation energy> of the compound nucleus. At finite incident energy, add the kinetic energy in the initial <centre-of-momentum frame>; in a nonrelativistic heavy-target approximation it is $A/(A+1)$ times the laboratory neutron kinetic energy. <Nuclear pairing> can significantly change capture excitation between neighboring even- and odd-mass targets.
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