Nuclidic mass formula on a spherical basis with an improved even-odd term

偶奇項を改良した球形基底原子核質量公式

小浦 寛之   ; 橘 孝博*; 宇野 正宏*; 山田 勝美*

Koura, Hiroyuki; Tachibana, Takahiro*; Uno, Masahiro*; Yamada, Masami*

われわれが2000年に発表した大局的項,平均的偶奇項,殻項を持つ質量公式の改良版を作成した。大局的部分は前回のものとほぼ同様であるが、偶奇項をより精密に取り扱い、相当の改善を行うことができた。殻項については前回のものと全く同様で、球形単一粒子ポテンシャルを用いて計算を行い、変形核については球形核の重ね合わせの考え方で取り扱うという方法を用いた。今回の質量公式は1及び1の核種に適用可能である。実験質量値との平均2乗誤差は0.658MeVとなり、前回の質量公式での誤差0.680MeVと比べて改善された。

A nuclidic mass formula composed of a gross term, an even-odd term and a shell term is presented as a revised version of the mass formula constructed by the present authors and published in 2000. The gross term has almost the same functional form as in the previous formula, but the parameter values in it are somewhat different. The even-odd term is treated more carefully, and a considerable improvement is brought about. The shell term is exactly the same as the previous one; it was obtained using spherical single-particle potentials and by treating the deformed nucleus as a superposition of spherical nuclei. The new mass formula is applicable to nuclei with 1 and 1. The root-mean-square deviation from experimental masses is 0.658 MeV, which is less than that of the previous mass formula, 0.680 MeV.