Institut des Sciences Moléculaires (ISM), UMR 5255, CNRS-Université Bordeaux I, 351, Cours de la Libération, Talence Cedex 33405, France.
J Chem Phys. 2010 Jul 21;133(3):034103. doi: 10.1063/1.3457483.
The present study is aimed at a detailed analysis of supercritical water structure based on the combination of experimental vibrational spectra as well as molecular modeling calculations of isolated water clusters. We propose an equilibrium cluster composition model where supercritical water is considered as an ideal mixture of small water clusters (n=1-3) at the chemical equilibrium and the vibrational spectra are expected to result from the superposition of the spectra of the individual clusters, Thus, it was possible to extract from the decomposition of the midinfrared spectra the evolution of the partition of clusters in supercritical water as a function of density. The cluster composition predicted by this model was found to be quantitatively consistent with the near infrared and Raman spectra of supercritical water analyzed using the same procedure. We emphasize that such methodology could be applied to determine the portion of cluster in water in a wider thermodynamic range as well as in more complex aqueous supercritical solutions.
本研究旨在基于实验振动光谱以及孤立水分子团的分子建模计算，对超临界水结构进行详细分析。我们提出了一种平衡团簇组成模型，其中超临界水被视为在化学平衡下小水分子团（n=1-3）的理想混合物，并且振动光谱预计将来自各个团簇光谱的叠加。因此，有可能从中红外光谱的分解中提取出超临界水中团簇的分布随密度的变化。通过这种模型预测的团簇组成被发现与使用相同方法分析的超临界水的近红外和拉曼光谱在定量上是一致的。我们强调，这种方法可以应用于确定更广泛的热力学范围内以及更复杂的水相超临界溶液中的团簇部分。
