Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany.
J Phys Chem A. 2010 Aug 19;114(32):8223-33. doi: 10.1021/jp104861q.
The gauche-trans conformational distribution in ethanol can be determined from the OH stretching Raman spectrum of seeded supersonic jet expansions, which thus provides a sensitive conformational thermometer. Depending on the rare gas mixture, one, two or four ethanol dimer conformations are abundant. Their conformational assignment is facilitated by the observation of hydrogen bond acceptor modes, which have similar Raman cross sections but much inferior infrared intensities than donor modes. Ethanol monomers and dimers can be progressively Ar-coated, and the resulting spectra may be compared with those in a bulk argon matrix. The low frequency range of torsional transitions provides some evidence for conformation-changing transitions in Raman jet spectra.
在乙醇中，可以通过种子超音速射流膨胀的 OH 伸缩拉曼光谱来确定 gauche-trans 构象分布，这为我们提供了一种灵敏的构象温度计。根据稀有气体混合物的不同，可以得到一种、两种或四种乙醇二聚体构象。通过观察氢键受体模式，有利于进行它们的构象分配，这些模式的拉曼截面相似，但与供体模式相比，红外强度要低得多。乙醇单体和二聚体可以逐步进行氩包裹，所得光谱可以与在块状氩基质中的光谱进行比较。扭转跃迁的低频范围为 Raman 射流光谱中的构象变化跃迁提供了一些证据。
