Scharge Tina, Cézard Christine, Zielke Philipp, Schütz Anne, Emmeluth Corinna, Suhm Martin A
Institut für Physikalische Chemie, Universität Göttingen, Tammannstr. 6, 37077, Göttingen, Germany.
Phys Chem Chem Phys. 2007 Aug 28;9(32):4472-90. doi: 10.1039/b705498j. Epub 2007 Jun 18.
Trifluoroethanol (TFE) and its aggregates are studied via supersonic jet FTIR and Raman spectroscopy as well as by quantum chemistry and simple force field approaches. A multi-slit nozzle is introduced to study collisionally excited clusters. Efforts are made to extract harmonic frequencies from experiment for better comparison to theory. Based on deuteration, the OH stretching anharmonicity changes weakly upon dimerization, but increases for trimers. Among the possible dimer conformations, only an all-gauche, homoconfigurational, compact, OH-F connected structure is observed in an extreme case of chiral discrimination. Quantum tunneling assisted pathways for this surprising helicity synchronization are postulated. The oscillator coupling in hydrogen-bonded trimers is analyzed. Trans conformations of TFE start to become important for trimers and probably persist in the liquid state. Simple force fields can be refined to capture some molecular recognition features of TFE dimer, but their limitations are emphasized.
通过超音速喷射傅里叶变换红外光谱和拉曼光谱以及量子化学和简单力场方法对三氟乙醇（TFE）及其聚集体进行了研究。引入了多缝喷嘴来研究碰撞激发的团簇。努力从实验中提取谐波频率以便更好地与理论进行比较。基于氘代，OH伸缩非谐性在二聚化时变化较弱，但在三聚化时增加。在可能的二聚体构象中，在手性识别的极端情况下，仅观察到一种全gauche、同构型、紧凑、OH-F连接的结构。推测了这种令人惊讶的螺旋同步的量子隧穿辅助途径。分析了氢键三聚体中的振子耦合。TFE的反式构象对三聚体开始变得重要，并且可能在液态中持续存在。可以改进简单力场以捕获TFE二聚体的一些分子识别特征，但强调了它们的局限性。
