Clarifying electronic and vibronic properties at the individual molecule level provides key insights for future chemistry, nanoelectronics and quantum information technologies. However, information obtained by conventional single-molecule transport measurements is based on time-averaged properties. Here, we report on terahertz (THz) spectroscopy of single fullerene molecules by using a single-molecule transistor geometry. From the time-domain THz autocorrelation measurements, we obtained THz spectra associated with the THz-induced centre-of-mass oscillation of the molecules. The observed spectra reflect the potential profile experienced by the molecule on the metal surface when the number of electrons on the molecule fluctuates by one during the single-electron tunnelling process. Such an ultra-high sensitivity to the electronic/vibronic structures of a single molecule on the addition/removal of a single electron has been achieved as a result of using THz spectroscopy in the single-molecule transistor geometry. This scheme provides an opportunity to investigate the ultrafast THz dynamics of subnanometre-scale systems.

在单个分子水平上阐明电子和振动学性质为未来化学，纳米电子学和量子信息技术提供了重要的见识。但是，通过常规单分子传输测量获得的信息是基于时间平均特性的。在这里，我们通过使用单分子晶体管几何形状来报告单个富勒烯分子的太赫兹（THz）光谱。从时域太赫兹自相关测量，我们获得了与太赫兹引起的分子质心振荡相关的太赫兹光谱。观察到的光谱反映了在单电子隧穿过程中，当分子上的电子数波动一个时，分子在金属表面上经历的电势分布。通过在单分子晶体管几何结构中使用太赫兹光谱技术，已经实现了在添加/去除单个电子时对单个分子的电子/振动结构的超高灵敏度。该方案为研究亚纳米级系统的超快THz动力学提供了机会。