The water structure around chloride ion investigated from D2O↔H2O substitution effect
The water structure around chloride ion investigated from D2O↔H2O substitution effect
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DOI：
10.1016/j.molliq.2022.120702
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发表时间：
2022-11
影响因子：
6
通讯作者：
Qingcheng Hu;Haiwen Zhao;S. Ouyang;Yuying Liang;Huimin Yang;Xuefeng Zhu
中科院分区：
文献类型：
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作者：
Qingcheng Hu;Haiwen Zhao;S. Ouyang;Yuying Liang;Huimin Yang;Xuefeng Zhu
在293 ~ 573 K温度范围内测量了（D2 O + H2O）− NaCl溶液（nH 2 O/nD 2 O = 0/1，1/4，1/1，4/1和1/0）的拉曼光谱。我们进一步讨论了水结构的解决方案的基础上溶质相关的（SC）OD/OH伸缩带从多元曲线分辨率方法。最突出的效果是H ParticipD替代提高了高波数模式的相对强度。在493 K以上，当同位素取代率为80%时，能使2660 cm-1/3635 cm-1模成为主峰。光谱特征表明Cl−水合壳层中存在灵活的水结构，其中大多数水合水分子都参与了单供体（SD）和单氢键水（SHW）的氢键构型。同位素取代率的增加导致了SD → SHW → FW（自由水）的结构转变，当同位素取代率为80%时，温度超过493 K，FW大大增加。此外，水合水的估计氢键数表明在水合壳层中D2 O-Cl-相互作用比H2O-Cl-相互作用更强。
The Raman spectra for (D2O + H2O) − NaCl solutions (nH2O/nD2O= 0/1, 1/4, 1/1, 4/1 and 1/0) were measured at temperatures from 293 to 573 K. We further discuss the water structure in the solutions based on the solute-correlated (SC) OD/OH stretch bands obtained from the Multivariate Curve Resolution method. The most prominent effect of H ↔ D substitution is raising the relative intensity of the high-wavenumber modes. The ∼ 2660 cm−1/∼3635 cm−1mode can become the main peak when isotopic substitution ratio is 80 % at temperatures over 493 K. The spectral features suggest a flexible water structure in the Cl−hydration shell where most hydrating water molecules are engaged in hydrogen bonding configurations of single donor (SD) and single hydrogen-bond water (SHW). The increase of isotopic substitution ratio leads to the structural transition of SD → SHW → FW (free water) so that FW is greatly increased at isotopic substitution ratio of 80 % and temperatures over 493 K. Moreover, the estimated hydrogen bond number for hydrating water indicates a stronger D2O − Cl−interaction than H2O − Cl−interaction in the hydration shell.