The Most Tightly Bound Nuclei

The most tightly bound of the nuclei is ⁶²Ni, a case made convincingly by M. P. Fewell in an article in the American Journal of Physics. Though the championship of nuclear binding energy is often attributed to ⁵⁶Fe, it actually comes in a close third. The four most tightly bound nuclides are listed in the table below with a tabulation of the binding energy B divided by the mass number A. The curve adapted from Fewell shows those nuclides that are close to the peak.

最紧密结合的原子核是62Ni，这一结论由M. P. Fewell在《美国物理期刊》上的一篇文章中得到了有力的证明。尽管核结合能的冠军常归于56Fe，但实际上它仅排在第三位。表下面列出了四个最紧密结合的核素，并给出了结合能B除以质量数A的统计结果。改编自Fewell的曲线显示了那些接近峰值的核素。

The most tightly bound nuclides are all even-even nuclei. The curve drawn through the cluster of nuclei above is just to show the nature of the trend with mass number. A similar kind of trend is observed with even-odd nuclides at a lower range of binding energy, and then by odd-odd nuclei at the least-bound extreme. The peaks of all three groups occur around A = 60.

最紧密结合的核都是偶-偶核。通过上述核团绘制的曲线只是为了显示质量数的趋势性质。在较低的结合能范围内，偶-奇核也表现出类似的趋势，而在最不结合的极端处，奇-奇核也显示出相同的趋势。这三个组的峰都出现在A = 60附近。

The high binding energy of this group of elements around A=60, typically called "the iron group" by astrophysicists, is significant in the understanding of the synthesis of heavy elements in the stars. It is curious that the abundance of ⁵⁶Fe is an order of magnitude higher than that of ⁶²Ni. Fewell discusses this point, and indicates that the reason lies with the greater photodisintegration rate for ⁶²Ni in stellar interiors.

这一组原子量约为60的元素具有较高的结合能，通常被称为‘铁组’，这对于理解恒星中重元素的合成具有重要意义。有趣的是，56Fe的丰度比62Ni高一个数量级。Fewell讨论了这一点，并指出原因在于62Ni在恒星内部的光解离率更高。