Measuring acetic acid dimer modes by ultrafast time-domain Raman spectroscopy
Measuring acetic acid dimer modes by ultrafast time-domain Raman spectroscopy
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DOI：
10.1039/c1cp20990f
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Meech, Stephen R.
中科院分区：
文献类型：
--
作者：
Heisler, Ismael A.;Mazur, Kamila;Meech, Stephen R.
乙酸能够形成强的多重氢键，因此在纯液相和溶液中形成不同的二聚氢键结构。通过超快时间和偏振分辨光学克尔效应 (OKE) 测量获得了乙酸的低频拉曼光谱（纯乙酸，在水溶液中且作为温度的函数）。各向同性 OKE 测量清楚地揭示了与二聚体结构氢键拉伸模式相关的特定完全对称模式。研究了同位素取代、水稀释和温度对该模式的影响。这些结果与各向异性 OKE 测量和许多可能的二聚体的密度泛函理论计算一起提供了强有力的证据，证明环状二聚体结构是液相中的主要结构，在乙酸浓度低至 10 M 的情况下持续存在。推断出有关二聚体结构和浓度依赖性的一些信息。
Acetic acid is capable of forming strong multiple hydrogen bonds and therefore different dimeric H-bonded structures in neat liquid phase and in solutions. The low frequency Raman spectra of acetic acid (neat, in aqueous solution and as a function of temperature) were obtained by ultrafast time and polarization resolved optical Kerr effect (OKE) measurements. Isotropic OKE measurements clearly reveal a specific totally symmetric mode related to the dimeric structure H-bond stretching mode. The effects of isotope substitution, water dilution and temperature on this mode were investigated. These results together with anisotropic OKE measurements and density functional theory calculations for a number of possible dimers provide strong evidence for the cyclic dimer structure being the main structure in liquid phase persisting down to acetic acid concentrations of 10 M. Some information about the dimer structure and concentration dependence was inferred.