# Novel evidence for the σ-bond linear-chain molecular structure in 14C

• A multi-nucleon transfer and cluster decay experiment, $^7$Li($^{11}$B,$^{14}$C$^*\rightarrow\alpha$+$^{10}$Be)$\alpha$, is conducted at an incident beam energy of 55 MeV. This reaction channel has a significantly large Q-value, which favors populating the high lying resonant states in $^{14}$C. The decay paths, from these resonances to various states of the final nucleus $^{10}$Be, can be selected, owing to the experimentally achieved optimal resolution of the Q-value spectrum. A number of resonant states are reconstructed from the forward emitting $^{10}$Be + $\alpha$ fragments, and their major molecular structures can be detected according to the selective decay paths and relative decay widths. A state at 22.4(2) MeV validates the previously measured and theoretically predicted band head of the positive-parity $\sigma$-bond linear-chain molecular band. Two additional resonances at 22.9(2) and 24.2(2) MeV are identified and consistent with the predicted $2^+$ and $4^+$ members of the same molecular band, thus providing novel evidences for the existence of the exotic clustering chain structure in neutron-rich carbon isotopes. A few high energy resonances, which also indicate the presence of the $\sigma$-bond molecular structure, are observed; however, further studies are still required to clarify their ascription in band systematics.
PCAS:
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Han-zhou Yu, Jing Li, Yan-Lin Ye, Biao Yang, Cheng-Jian Lin, Hui-Ming Jia, Jian-Ling Lou, Xiao-Fei Yang, T. Baba, Qi-Te Li, Yu-Cheng Ge, Zhi-Huan Li, Hui Hua, Jin-Yan Xu, Zai-Hong Yang, Jun Feng, Hong-Liang Zang, Qiang Liu, Wei Jiang, Yang Liu, Jing-Jing Li, Wei Liu, Shi-Wei Bai, Jie Chen, Jia-Xing Han, Jia-Hao Chen, Kai Ma, Dong-Xi Wang, Lei Yang, Nan-Ru Ma and LI-Jie Sun. New evidences for the σ-bond linear-chain molecular structure in 14C[J]. Chinese Physics C. doi: 10.1088/1674-1137/ac04a0
Han-zhou Yu, Jing Li, Yan-Lin Ye, Biao Yang, Cheng-Jian Lin, Hui-Ming Jia, Jian-Ling Lou, Xiao-Fei Yang, T. Baba, Qi-Te Li, Yu-Cheng Ge, Zhi-Huan Li, Hui Hua, Jin-Yan Xu, Zai-Hong Yang, Jun Feng, Hong-Liang Zang, Qiang Liu, Wei Jiang, Yang Liu, Jing-Jing Li, Wei Liu, Shi-Wei Bai, Jie Chen, Jia-Xing Han, Jia-Hao Chen, Kai Ma, Dong-Xi Wang, Lei Yang, Nan-Ru Ma and LI-Jie Sun. New evidences for the σ-bond linear-chain molecular structure in 14C[J]. Chinese Physics C.
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###### 通讯作者: 陈斌, bchen63@163.com
• 1.

沈阳化工大学材料科学与工程学院 沈阳 110142

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## Novel evidence for the σ-bond linear-chain molecular structure in 14C

###### Corresponding author: Yan-Lin Ye, yeyl@pku.edu.cn
• 1. School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
• 2. FRIB/NSCL Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
• 3. China Institute of Atomic Energy, Beijing 102413, China
• 4. Kitami Institute of Technology, 090-8507 Kitami, Japan
• 5. Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
• 6. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
• 7. Spallation Neutron Source Science Center, Dongguan 523803, China

Abstract: A multi-nucleon transfer and cluster decay experiment, $^7$Li($^{11}$B,$^{14}$C$^*\rightarrow\alpha$+$^{10}$Be)$\alpha$, is conducted at an incident beam energy of 55 MeV. This reaction channel has a significantly large Q-value, which favors populating the high lying resonant states in $^{14}$C. The decay paths, from these resonances to various states of the final nucleus $^{10}$Be, can be selected, owing to the experimentally achieved optimal resolution of the Q-value spectrum. A number of resonant states are reconstructed from the forward emitting $^{10}$Be + $\alpha$ fragments, and their major molecular structures can be detected according to the selective decay paths and relative decay widths. A state at 22.4(2) MeV validates the previously measured and theoretically predicted band head of the positive-parity $\sigma$-bond linear-chain molecular band. Two additional resonances at 22.9(2) and 24.2(2) MeV are identified and consistent with the predicted $2^+$ and $4^+$ members of the same molecular band, thus providing novel evidences for the existence of the exotic clustering chain structure in neutron-rich carbon isotopes. A few high energy resonances, which also indicate the presence of the $\sigma$-bond molecular structure, are observed; however, further studies are still required to clarify their ascription in band systematics.

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