Hydrogen bond dynamics of superheated water and methanol by ultrafast IR-pump and EUV-photoelectron probe spectroscopy.
Hydrogen bond dynamics of superheated water and methanol by ultrafast IR-pump and EUV-photoelectron probe spectroscopy.
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通过超快红外泵和 EUV 光电子探针光谱研究过热水和甲醇的氢键动力学
DOI：
10.1039/c4cp02063d
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Grub-muller
中科院分区：
文献类型：
--
作者：
Vohringer-Martinez;Lugovoy;Siefermann;Wiederschein;Grub-muller
超临界水和甲醇是近年来绿色化学研究的热点。了解超临界溶剂的动力学和氢键在这些流体中存在的程度是至关重要的。在这里，我们证明了用飞秒红外（IR）激光脉冲可以将水和甲醇加热到接近或高于其临界温度Tc的温度，并且可以在高谐波辐射的液体射流界面上通过超快光电子能谱研究它们的分子动力学。与以往的研究相反，这里的主要重点是甲醇和水的氢键系统的比较及其理论解释。过热水最初形成致密的热相，其光谱特征类似于气相水中的单体。在更长的时间尺度上，这一阶段被发现会形成热聚集体，其大小随着时间的推移而增加。相比之下，甲醇加热到接近Tc的温度，最初形成广泛分布的聚集体尺寸和一些气体。在扩展的分子动力学模拟中也发现并分析了这些实验特征。此外，模拟使我们能够将这两种氢键液体的不同行为的起源与分子间电位的性质联系起来。实验和理论相结合的方法为这两个过热相提供了新的见解，并可能有助于理解它们不同的化学反应。
Supercritical water and methanol have recently drawn much attention in the field of green chemistry. It is crucial to an understanding of supercritical solvents to know their dynamics and to what extent hydrogen (H) bonds persist in these fluids. Here, we show that with femtosecond infrared (IR) laser pulses water and methanol can be heated to temperatures near and above their critical temperature Tc and their molecular dynamics can be studied via ultrafast photoelectron spectroscopy at liquid jet interfaces with high harmonics radiation. As opposed to previous studies, the main focus here is the comparison between the hydrogen bonded systems of methanol and water and their interpretation by theory. Superheated water initially forms a dense hot phase with spectral features resembling those of monomers in gas phase water. On longer timescales, this phase was found to build hot aggregates, whose size increases as a function of time. In contrast, methanol heated to temperatures near Tc initially forms a broad distribution of aggregate sizes and some gas. These experimental features are also found and analyzed in extended molecular dynamics simulations. Additionally, the simulations enabled us to relate the origin of the different behavior of these two hydrogen-bonded liquids to the nature of the intermolecular potentials. The combined experimental and theoretical approach delivers new insights into both superheated phases and may contribute to understand their different chemical reactivities.
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DOI：
10.1016/s0022-0728(74)80356-6
发表时间：
1974-01
期刊：
--
影响因子：
--
作者：
R. Parsons
通讯作者：
R. Parsons
影响因子：
8.6
作者：
S. Thürmer;R. Seidel;M. Faubel;W. Eberhardt;J. Hemminger;S. Bradforth;B. Winter
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用于液态水界面附近化学分析的超快电子光谱：概念和应用
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
O. Link;E. Lugovoy;K. Siefermann;Y. Liu;M. Faubel;B. Abel
通讯作者：
B. Abel
影响因子：
6.3
作者：
BERENDSEN, HJC;VANDERSPOEL, D;VANDRUNEN, R
通讯作者：
VANDRUNEN, R
极端条件下的化学反应
DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
M. Manaa
通讯作者：
M. Manaa