Simulations and Spectra of Water in CO Matrices
Simulations and Spectra of Water in CO Matrices
复制标题
CO 基质中水的模拟和光谱
DOI：
10.1039/c6cp08248c
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发表时间：
2017
影响因子：
3.3
通讯作者：
and N Watanabe
中科院分区：
文献类型：
--
作者：
R. Escribano;E. Artacho;A. Kouchi;T. Hama;Y. Kimura;H. Hidaka;and N Watanabe
使用应用于无定形固体系统的密度泛函理论开发了一氧化碳基质中包含水分子的模型。这些模型涵盖了具有不同含水量的较小或较大 CO 基质的大范围系统，由单个 H2O 分子或通过氢键连接的小簇组成。样品的振动谱是在其势能表面的最小值处预测的。光谱可以辨别水分子保持孤立或形成聚集体的情况，并且它们还可以指示氢键（如果存在）的强度。这些计算支持了最近的实验观察结果，该观察结果将 3707 cm−1 和 3617 cm−1 的红外波段与贫水 CO/H2O 混合冰中未结合水分子的存在联系起来。还建议将一些观察到的条带分配给水二聚体或三聚体。还计算了固定体积模拟单元中的残余静压。
Models for the inclusion of water molecules in carbon monoxide matrices are developed using density functional theory applied to amorphous solid systems. The models cover a large range of systems for smaller or larger CO matrices with different water content, consisting of either individual H2O molecules or small clusters linked by H-bonds. The vibrational spectra of the samples are predicted at the minimum of their potential energy surface. The spectra allow instances where the water molecules remain isolated or form aggregates to be discerned, and they also provide an indication of the strength of the H-bonding, when present. The calculations support recent experimental observations that linked IR bands at 3707 cm−1 and 3617 cm−1 to the presence of unbound water molecules in water-poor CO/H2O mixed ices. Assignment of some observed bands to water dimers or trimers is suggested as well. The residual static pressure in fixed-volume simulation cells is also calculated.