Mousavi Seyyed Jabbar, Berger Arian, Hamm Peter, Shalit Andrey
Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
J Chem Phys. 2022 May 7;156(17):174501. doi: 10.1063/5.0090520.
Two-dimensional (2D) Raman-THz spectroscopy in the frequency of up to 7 THz has been applied to study the crystalline β-phase of bromoform (CHBr). As for liquid CHBr, cross peaks are observed, which, however, sharpen up in the crystalline sample and split into assignable sub-contributions. In the Raman dimension, the frequency positions of these cross peaks coincide with the intramolecular bending modes of the CHBr molecules and in the THz dimension with the IR-active lattice modes of the crystal. This work expands the applicability of this new 2D spectroscopic technique to solid samples at cryogenic temperatures. Furthermore, it provides new experimental evidence that the cross peaks, indeed, originate from the coupling between intra- and intermolecular vibrational modes.
二维（2D）拉曼-太赫兹光谱在高达7太赫兹的频率范围内已被用于研究溴仿（CHBr₃）的晶体β相。对于液态CHBr₃，观察到了交叉峰，然而，这些交叉峰在晶体样品中变尖锐并分裂为可识别的子成分。在拉曼维度中，这些交叉峰的频率位置与CHBr₃分子的分子内弯曲模式一致，在太赫兹维度中与晶体的红外活性晶格模式一致。这项工作将这种新的二维光谱技术的适用性扩展到了低温下的固体样品。此外，它提供了新的实验证据，证明交叉峰确实源于分子内和分子间振动模式之间的耦合。
