Abstract-Multiple Sharp Terahertz Absorption Peaks in Rhombic Sulfur Detected Using High-resolution Terahertz Spectroscopy

Arata Yasuda, Tetsuo Sasaki,

https://www.sciencedirect.com/science/article/abs/pii/S000926141930925X

We investigated rhombic sulfur (S) using a tunable, coherent, terahertz (THz) frequency spectroscopic system (0.6–6.0 THz) herein. At 70 K, we detected unique absorbance peaks in the spectra around 1.3, 2.2, 2.4, 4.5, 5.5, and 5.9 THz, which shifted to higher frequencies with decreasing temperature. Density-functional theory (DFT) calculations revealed unique triple peaks at approximately 5.6, 5.8 and 5.9 THz. The sharp and strong absorbance that produced the multiple peaks can be attributed to intramolecular twisting and deformation vibrations of the S8 ring structure. Many unique peaks originating from intermolecular vibrations of S8 were obtained in the lower-frequency region.