Effect of charge polarization on the coulomb barrier for cold-fusion reactions

コールドフュージョン反応におけるクーロン障壁への電荷分極の効果

市川 隆敏; 岩本 昭

Ichikawa, Takatoshi; Iwamoto, Akira

コールドフュージョン反応の入口チャネルでの電荷分極が原因で生じるクーロン障壁の高さの減少を見積もった。超重核合成のための重イオン反応では入射核と標的核の陽子数の増加とともにクーロン反発力が大きくなるので、電荷分極が生じると考えられる。生じた電荷分極は衝突間のクーロン相互作用エネルギーを減少させる一方、標的核と入射核の自己エネルギーは対称エネルギーの増加のために増加する。われわれは生じる電荷の変位は表面と体積電荷成分の和と仮定して、自己エネルギーはDropletモデルを用いて電荷分極の大きさを見積もった。本論文中で軽い核と重い核の電荷分極の違いと、超重核合成に関するクーロン障壁の高さの減少を見積もる。

We estimate the decrease of the Coulomb-barrier height between colliding parters due to charge polarizations in the entrance channel for cold-fusion reactions. Since the Coulomb-repulsion force increases with increasing the proton numbers of the target and projectile such as cold-fusion reactions, it is expected that the charge distribution of the colliding nuclei is changed to some extent. The resulting charge distribution induced by this polarization decreases the interacting Coulomb energy between the colliding partners, whereas their own self energies increase due to the increase of the symmetry energy. We assume that the resulting charge displacements between protons and neutrons are the sum of the surface- and volume-charge components and estimate the extent of the charge polarization with the self energy on the basis of the droplet model. We show the difference between the charge polarization of light and heavy nuclei and the decrease of the Coulomb barrier height for synthesizing superheavy elements.