Marabotti P, Tommasini M, Castiglioni C, Serafini P, Peggiani S, Tortora M, Rossi B, Li Bassi A, Russo V, Casari C S
Micro and Nanostructured Materials Laboratory-NanoLab, Department of Energy, Politecnico di Milano via Ponzio 34/3, I-20133, Milano, Italy.
Department of Chemistry, Materials and Chem. Eng. 'G. Natta', Politecnico di Milano Piazza Leonardo da Vinci 32, I-20133, Milano, Italy.
Nat Commun. 2022 Aug 27;13(1):5052. doi: 10.1038/s41467-022-32801-3.
UV resonance Raman spectroscopy of size-selected linear sp-carbon chains unveils vibrational overtones and combinations up to the fifth order. Thanks to the tunability of the synchrotron source, we excited each H-terminated polyyne (HCH with n = 8,10,12) to the maxima of its vibronic absorption spectrum allowing us to precisely determine the electronic and vibrational structure of the ground and excited states for the main observed vibrational mode. Selected transitions are shown to enhance specific overtone orders in the Raman spectrum in a specific way that can be explained by a simple analytical model based on Albrecht's theory of resonance Raman scattering. The determined Huang-Rhys factors indicate a strong and size-dependent electron-phonon coupling increasing with the sp-carbon chain length.
对尺寸选择的线性sp碳链进行紫外共振拉曼光谱分析，揭示了高达五阶的振动泛音和组合。得益于同步加速器光源的可调谐性，我们将每个氢端基聚炔（n = 8、10、12的HCH）激发至其振动电子吸收光谱的最大值，从而能够精确确定主要观察到的振动模式的基态和激发态的电子和振动结构。选定的跃迁以特定方式增强了拉曼光谱中的特定泛音阶次，这可以通过基于阿尔布雷希特共振拉曼散射理论的简单分析模型来解释。所确定的黄-里斯因子表明，电子-声子耦合很强且与尺寸有关，并随sp碳链长度增加。
