Tonauer Christina M, Köck Eva-Maria, Gasser Tobias M, Fuentes-Landete Violeta, Henn Raphael, Mayr Sophia, Kirchler Christian G, Huck Christian W, Loerting Thomas
Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria.
Max-Planck-Institut für Chemische Energiekonversion, D-45470 Mülheim an der Ruhr, Germany.
J Phys Chem A. 2021 Feb 4;125(4):1062-1068. doi: 10.1021/acs.jpca.0c09764. Epub 2021 Jan 5.
High-pressure ice polymorphs are important for our understanding of hydrogen bonding and exist in the interior of the earth and icy moons. Nonetheless, spectroscopic information about them is scarce, where no information about their optical properties in the near-infrared (NIR) region is available at all. We here report NIR spectra of six ice polymorphs differing in terms of their density and O-atom topology, namely, ices II, IV, V, VI, IX, and XII, in comparison with the known spectra of ice I. By contrast to earlier work, we do not use mulling agents or transmission of thin films but use diffuse reflectance on powdered samples in liquid nitrogen. The first overtone of the OH-stretching mode is identified as the marker band most suitable to distinguish between these ices. There is a clear blue shift of this band that increases with increasing topological density in addition to a significant narrowing of the band.
高压冰多晶型物对于我们理解氢键至关重要，且存在于地球内部和冰卫星中。尽管如此，关于它们的光谱信息却很稀少，完全没有关于其近红外（NIR）区域光学性质的信息。我们在此报告了六种密度和氧原子拓扑结构不同的冰多晶型物的近红外光谱，即冰II、IV、V、VI、IX和XII，并与已知的冰I光谱进行了比较。与早期工作不同的是，我们不使用研磨剂或薄膜透射，而是在液氮中对粉末样品使用漫反射。OH伸缩振动模式的第一泛音被确定为最适合区分这些冰的标记带。除了该带显著变窄外，随着拓扑密度的增加，该带还有明显的蓝移。
