合成Z=112-120超重核的热熔合反应中准裂变动力学的微观研究
Microscopic study of quasifission dynamics in hot fusion reactions for synthesizing superheavy nuclei with Z = 112-120
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中文总结 AI 辅助
本研究采用微观时间相关哈特利-福克理论，探究18种合成Z=112-120超重核的热熔合反应的准裂变动力学，明确壳层效应的关键作用及弹核质量对反应的影响，阐明Z=119、120合成反应的准裂变机制。
中文摘要 AI 辅助
在通过重离子熔合反应合成超重元素（SHE）的过程中，准裂变是阻碍超重核（SHN）形成的主要因素之一，且该过程的机制十分复杂。我们采用微观时间相关哈特利-福克（time-dependent Hartree-Fock）理论，对共18种反应中合成Z=112-120超重核的热熔合反应里的准裂变动力学展开研究。值得注意的是，这些反应中重碎片的核子数分布紧密围绕特定量子壳层，凸显了壳效应对碎片形成的关键作用。在使用48Ca、45Sc、50Ti和51V作为弹核的反应中，重碎片的形成主要由208Pb的双球形壳层驱动；相比之下，在54Cr诱发的反应中，Z=88和N=136的双八极形变壳层的影响更为显著，导致产生梨形224Ra重碎片的趋势。此外，使用更重弹核的反应中，碰撞系统往往会发生更快的准裂变，这可能是弹核重于48Ca的反应中熔合概率和合成截面显著降低的原因。这些结果阐明了合成新SHE Z=119和Z=120反应背后的准裂变机制。
英文摘要
In the synthesis of superheavy element (SHE) via heavy-ion fusion reactions, quasifission is one of the major factors hindering superheavy nuclei (SHN) formation and the mechanism behind this process is intricate. We investigate dynamics of quasifission in hot fusion reactions synthesizing SHN with Z = 112-120 using microscopic time-dependent Hartree-Fock theory in a total of 18 reactions. Remarkably, the nucleon numbers of heavy fragments distribute closely around certain quantum shells in these reactions, highlighting the crucial role of shell effects in fragment formation. In the reactions with 48Ca, 45Sc, 50Ti and 51V projectiles, the formation of heavy fragment is dominantly driven by the double spherical shells of 208Pb. In contrast, the influence of the double octupole deformed shells at Z = 88 and N = 136 is more pronounced in 54Cr-induced reactions, resulting in a tendency of producing pear-shaped 224Ra heavy fragment. Moreover, in the reaction with a heavier projectile, the colliding system tends to undergo a more rapid quasifission. This may be responsible for significantly reduced fusion probability and synthesis cross section observed in the reactions with projectiles heavier than 48Ca. These results elucidate quasifission mechanisms behind the reactions for synthesizing new SHEs Z = 119 and Z = 120.
