The role of correlation entropy in nuclear fusion in liquid lithium, indium and mercury

Nuclear fusion cross-sections considerably higher than corresponding theoretical predictions are observed in low-energy experiments with metal matrix targets and accelerated deuteron beams. The cross-section increment is significantly higher for liquid than for solid targets. We propose that the same two-body correlation entropy used in evaluating the metal melting entropy explains the large liquid-solid difference of the effective screening potential that parameterizes the cross-section increment. This approach is applied to the specific case of the $^6$Li(d,$\alpha$)$^4$He reaction, whose measured screening potential liquid-solid difference is $(235 \pm 63)$ eV. Cross sections in the two metals with the highest two-body correlation entropy (In and Hg) have not yet been measured: increments of the cross sections in liquid relative to the ones in solid metals are estimated with the same procedure.