Up to now, at least 806 carbon allotropes have been proposed theoretically. Three interesting carbon allotropes (named Pbam -32, P 6/ mmm , and ##IMG## [http://ej.iop.org/images/1674-1056/29/9/093601/cpb_29_9_093601_ieqn1.gif] {$I\bar{4}3d$} ) were recently uncovered based on a random sampling strategy combined with space group and graph theory. The calculation results show that they are superhard and remarkably stable compared with previously proposed metastable phases. This indicates that they are likely to be synthesized in experiment. We use the factor group analysis method to analyze their Γ -point vibrational modes. Owing to their large number of atoms in primitive unit cells (32 atoms in Pbam -32, 36 atoms in P 6/ mmm , and 94 atoms in ##IMG## [http://ej.iop.org/images/1674-1056/29/9/093601/cpb_29_9_093601_ieqn1.gif] {$I\bar{4}3d$} ), they have many Raman- and infrared-active modes. There a...

中文翻译：

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根据第一性原理计算的复杂低能四面体碳同素异形体的拉曼光谱和红外光谱

到目前为止，理论上已经提出了至少806个碳同素异形体。三种有趣的碳同素异形体（命名为Pbam -32，P 6 / mmm和## IMG ## [http://ej.iop.org/images/1674-1056/29/9/093601/cpb_29_9_093601_ieqn1.gif] I \ bar {4} 3d $}）是最近结合空间组和图论的随机抽样策略发现的。计算结果表明，与先前提出的亚稳态相相比，它们具有超硬性和显着的稳定性。这表明它们很可能在实验中合成。我们使用因子组分析方法来分析它们的Γ点振动模式。由于它们在原始晶胞中有大量原子（Pbam -32中为32个原子，P 6 / mmm中为36个原子，## IMG ##中为94个原子[http://ej.iop.org/images/1674 -1056 / 29/9/093601 / cpb_29_9_093601_ieqn1.gif] {$ I \ bar {4} 3d $}），他们有许多拉曼和红外激活模式。那里...