绘制 C₆₀ 中分子间键合的图谱。

Mapping intermolecular bonding in C₆₀.

机构信息

Department of Physics, Umeå University, S-90187 Umeå, Sweden.

出版信息

Sci Rep. 2014 Aug 22;4:6171. doi: 10.1038/srep06171.

DOI:10.1038/srep06171

PMID:25145952

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC4141248/

Abstract

The formation of intermolecular bonds in C₆₀ has been investigated in detail at pressures below 2.2 GPa and up to 750 K. Fullerene samples were heated in a temperature gradient to obtain data on the formation of dimers and low-dimensional polymers along isobars. Intermolecular bonding was analyzed ex situ by Raman scattering, using both intramolecular modes and intermolecular stretching modes. Semi-quantitative reaction maps are given for the formation of dimers and chains. The activation energy for dimer formation decreases by 0.2 meV pm(-1) when intermolecular distances decrease and dimer formation is noticeably affected by the rotational state of molecules. Above 400-450 K larger oligomers are formed; below 1.4 GPa most of these are disordered, with small domains of linear chains, but above this the appearance of stretching modes indicates the existence of ordered one-dimensional polymers. At the highest pressures and temperatures two-dimensional polymers are also observed.

摘要

在 2.2 GPa 以下和 750 K 以下的压力下，详细研究了 C₆₀ 中分子间键的形成。通过在温度梯度中加热富勒烯样品，在等压线上获得了关于二聚体和低维聚合物形成的数据。通过拉曼散射对分子间键进行了非原位分析，同时使用了分子内模式和分子间伸缩模式。给出了二聚体和链形成的半定量反应图。当分子间距离减小时，二聚体形成的活化能降低 0.2 meV pm(-1)，并且二聚体的形成明显受到分子旋转状态的影响。在 400-450 K 以上形成较大的齐聚物；在 1.4 GPa 以下，大多数都是无序的，只有少量线性链的小区域，但在这之上，伸缩模式的出现表明存在有序的一维聚合物。在最高的压力和温度下，也观察到二维聚合物。