S-factor

In

The quantity is defined as[1]

${\displaystyle S(E)\equiv {\frac {E}{\exp(-2\pi \eta )}}\sigma (E)}$,

where E is the energy, σ is the cross section, η is the dimensionless Sommerfeld parameter:

${\displaystyle \eta \equiv {\frac {Z_{1}Z_{2}e^{2}}{4\pi \epsilon _{0}\hbar v}}}$,

Z₁ Z₂ e² is the product of the charges of the reactants, ${\displaystyle \epsilon _{0}}$ is the

${\displaystyle \hbar }$

The Coulomb barrier causes the cross section to have a strong exponential dependence on the center-of-mass energy E. The S-factor remedies this by factoring out the Coulomb component of the cross section.

References