On the Positive-Parity States with Anomalous α-Decay Properties in 12C
On the Positive-Parity States with Anomalous α-Decay Properties in 12C
复制标题
DOI：
10.1143/ptp.59.1031
复制
发表时间：
1978-03
影响因子：
--
通讯作者：
E. Uegaki;Y. Abe;S. Okabe;Hajime Tanaka-
中科院分区：
文献类型：
--
作者：
E. Uegaki;Y. Abe;S. Okabe;Hajime Tanaka-
12C核中7.7和10.3 MeV的激发正宇称能级以其异常大的a-衰变宽度而闻名，它们被认为是典型的a-聚类态，这很容易被池田图所预料，并从理论上进行了研究。但不幸的是，实验资料是如此稀少，以至于10.3兆电子伏能级的自旋至今尚未确定。从a-聚类期望的角度出发，利用生成坐标法（GCM）从微观上研究了a-粒子体系的动力学性质。得到了02 +、22 +、03 +、23 +、42 +、31 +等激发态（参考文献5），以下简称1)。本文的目的是研究这些态的a-衰变性质，并阐明12C这一能区激发态的核结构。在图1中，通过GCM计算得到的能谱1表明，22 +态是02 +态的下一个正宇称态。03 +态和简并的23 +态比02 +态高约4mev。对于大间距，基波函数的截断不会改变这种情况。与实验相比l __ o · __________________ o·
The excited positive-parity levels at 7.7 and 10.3 MeV in 12C nucleus are famous for their anomalously large a-decay widthsY They have been considered to be typical states with a-clustering, which is readily expected by Ikeda diagram, 'l and investigated theoretically.3l But unfortunately experimental information is so rare that the spin of the 10.3 MeV level is not established as yet.'l On the standpoint of a-clustering expected, we have studied dynamical properties of 3 a-particle system microscopically by using the generator coordinate method (GCM). And we have obtained the excited positive-parity states, 02 +, 22 +, 03 +, 23 +, 42 + and 31 + (Ref. 5), hereafter referred to as I) . The purpose of the present paper is to investigate a-decay properties of these states and to clarify nuclear structure of excited states in this energy region of 12C. In Fig. 1 an energy spectrum obtained by the GCM calculation I shows that the 22 + state is the next positive-parity state of the 02 + state. The 03 + state comes out about 4 MeV high above the 02 + state together with the degenerate 23 + state. This situation is not changed by any truncation of the basis wave functions for large intera-distances. Compared with experiment l __ o· __________________ o·