Raman Spectroscopy of Size-Selected Linear Polyyne Molecules C2nH2 (n = 4−6) Encapsulated in Single-Wall Carbon Nanotubes
Raman Spectroscopy of Size-Selected Linear Polyyne Molecules C2nH2 (n = 4−6) Encapsulated in Single-Wall Carbon Nanotubes
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DOI：
10.1021/jp0686442
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发表时间：
2007-03
影响因子：
3.7
通讯作者：
D. Nishide;Tomonari Wakabayashi;T. Sugai;R. Kitaura;H. Kataura;Y. Achiba;H. Shinohara
中科院分区：
文献类型：
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作者：
D. Nishide;Tomonari Wakabayashi;T. Sugai;R. Kitaura;H. Kataura;Y. Achiba;H. Shinohara
通过拉曼光谱研究了单壁碳纳米管（SWNT）中的聚炔分子（C2 nH 2，n = 4−6）。在2000 - 2200 cm-1区域观察到的拉曼谱带被认为是线性碳分子的轴向拉伸基本原理ν2-ν4（D∞h中的σg）。对于C_（10）H_2和C_（12）H_2，还观察到在4100 cm ~（-1）处的泛音带和在3600 cm ~（-1）处的聚炔模和石墨模的组合带。双声子激发可能是负责观察到的共振拉曼峰通过新的电子状态所产生的封装的多炔和纳米管之间施加的色散相互作用。单壁碳纳米管中聚炔分子的振动频率随碳纳米管直径分布的减小而增大。这种相互作用也是导致观察到的频率偏移和拉曼带展宽的原因。
Polyyne molecules (C2nH2, n = 4−6) encaged inside single-wall carbon nanotubes (SWNTs) are investigated by Raman spectroscopy. The Raman bands observed in the region of 2000−2200 cm-1 are identified as due to axial-stretching fundamentals, ν2−ν4 (σg in D∞h), of the linear carbon molecules. For C10H2 and C12H2, the overtone bands at ∼4100 cm-1 and combination bands of the polyyne and graphitic modes at ∼3600 cm-1 are also observed. The two-phonon excitations may be responsible for the observed resonance Raman peaks via new electronic states generated by the dispersion interaction exerted between encapsulated polyynes and nanotubes. The vibrational frequencies of the polyyne molecules in SWNTs increase as the diameter distributions of SWNTs decrease. The interaction is also responsible for the observed frequency shifts and broadening of the Raman bands.