Macroscopic Quantum Tunneling in Nuclear Physics

1. 我们通过研究^<144>Sm的双声子四极和八极激发对^<16>O+^<144>Sm在库仑势垒以下能量下的聚变反应的影响，证明了核表面振动的非调和性强烈影响聚变势垒分布。利用这一结果，我们推导出^<144>Sm的2 +态和3 -态的负四极矩。我们对^<16>O+^<148>Sm聚变反应进行了类似的分析。2. 我们研究了激发态的有限宽度对库仑势垒附近和库仑势垒以下能量的重离子聚变反应的影响，结果表明，无论扩散宽度和逃逸宽度的相对重要性如何，激发态的有限宽度总是降低通道耦合的增强效应。3. 我们分析了^<16>O+^<154>Sm, ^<186>W ^<238>U低能聚变反应。β - 6-变形、八极子振动和2核子转移反应起着重要的作用。4. 我们对α衰变中的轫致辐射进行了研究，结果表明：(1)经典区、隧道区、混合区和壁的贡献都起着重要的作用；(2)最终谱是由它们的干涉给出的，比经典值小得多；(3)轫致辐射可以消除确定α粒子和子核之间势的模糊性。5. 我们证明了在极前角区核彩虹的阴影引起的一种类似荣光的现象是一种新的焦散现象。6. 此外，我们还研究了(1)核不可压缩性的同位旋依赖性；(2)极低能核反应中束缚电子的筛选效应；(3)与裂变和重离子碰撞有关的跨二能级问题的非绝热跃迁；(4)金属团簇中的电子态；(5)中能重离子碰撞中的碎裂。

1. We showed that the anharmonicity of nuclear surface vibrations strongly influences the fusion barrier distribution by studying the effects of double phonon quadrupole and octupole excitations of ^<144>Sm on the ^<16>O+^<144>Sm fusion reactions at energies below the Coulomb barrier. Using this result, we deduced a negative quadrupole moment for both first excited 2^+ and 3^- states of ^<144>Sm. We performed a similar analysis for the ^<16>O+^<148>Sm fusion reactions. 2. We studied the influence of finite width of excited states on heavy-ion fusion reactions at energies near and below the Coulomb barrier, and showed that the finite width always reduces the enhancement effect of the channel coupling irrespective of the relative importance of the spreading and escape widths. 3. We analyzed the ^<16>O+^<154>Sm, ^<186>W ^<238>U fusion reactions at low energies and showed that.beta_6- deformation, octupole as well as beta and gamma vibrations and 2 nucleon transfer reactions play important roles. 4. We studied the bremsstrahlung in alpha decay and showed that (1) all the contributions from the classical region, tunneling region, mixed region and the wall play important roles (2) the final spectrum is given by their interference and becomes much smaller than the classical value (3) the bremsstrahlung might eliminate the ambiguity in determining the potential between the alpha particle and the daughter nucleus. 5. We showed the existence of a glory-like phenomenon caused by the shadow of a nuclear rainbow in the extremely forward angular region as a novel caustic phenomenon. 6. In addition, we studied (1) isospin dependence of nuclear incompressibility (2) screening effect by bound electrons in extremely low energy nuclear reactions (3) non-adiabatic transition in crossing two-level problems in connection with fission and heavy-ion collisions (4) electron states in metal clusters and (5) fragmentation in medium energy heavy-ion collisions.