arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2104.09747astro-ph.GAcond-mat.mes-hallcond-mat.mtrl-sci
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多环芳烃碳材料3的空穴缺陷诱导磁性和结构变化

Void defect induced magnetism and structure change of carbon material-3, Polycyclic aromatic hydrocarbon

Norio Ota, Aigen Li, Laszlo Nemes

摘要:

在本系列研究的前一篇论文中,我们报道了石墨烯分子的空穴缺陷诱导磁性。本文研究了氢化石墨烯分子的情况,在化学术语中,多环芳烃(PAH)。用密度泛函理论得到的分子红外光谱与天文观测结果进行了比较。PAH上的孔洞缺陷引起了严重的结构变化。典型的例子C23 H12在六边形网络中有两个碳五边形环。稳定的自旋态为非磁性单重态。这与C23的纯碳情况相反,其显示磁性三重态。讨论了氢通过在SP2-网络之间形成SP3-键而起到减磁的重要作用。这种结构变化影响了分子的振动,并最终影响到红外区的光电子谱。指示剂-C23 H12在3.2、6.3、7.7、8.6、11.2和12.7微米处显示特征带。令人惊讶的是,这些计算出的谱带与天文学在许多行星状星云中观察到的谱带吻合得很好。为了证实我们的研究,研究了C53 H18的大分子。计算再次再现了类似的天文波段。此外,小尺寸分子的C12 H8表现出良好的符合观测到的年轻恒星的光谱。这份文件将是第一份指出空间中具体PAH的报告。

英文摘要:

Void-defect induced magnetism of graphene molecule was recently reported in our previous paper of this series study. This paper investigated the case of hydrogenated graphene molecule, in chemical term, polycyclic aromatic hydrocarbon (PAH). Molecular infrared spectrum obtained by density functional theory was compared with astronomical observation. Void-defect on PAH caused serious structure change. Typical example of C23H12 had two carbon pentagon rings among hexagon networks. Stable spin state was non-magnetic singlet state. This is contrary to pure carbon case of C23, which show magnetic triplet state. It was discussed that Hydrogen played an important role to diminish magnetism by creating an SP3-bond among SP2-networks. Such a structure change affected molecular vibration and finally to photoemission spectrum in infrared region. The dication-C23H12 showed featured bands at 3.2, 6.3, 7.7, 8.6, 11.2, and 12.7 micrometer. It was surprising that those calculated bands coincided well with astronomically observed bands in many planetary nebulae. To confirm our study, large size molecule of C53H18 was studied. Calculation reproduced again similar astronomical bands. Also, small size molecule of C12H8 showed good coincidence with the spectrum observed for young stars. This paper would be the first report to indicate the specific PAH in space.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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