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arXiv 1611.03384cond-mat.softcond-mat.mtrl-sciphysics.chem-ph
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二次谐波散射对液体结构相关性的研究

Second-Harmonic Scattering as a Probe of Structural Correlations in Liquids

Gabriele Tocci, Chungwen Liang, David M. Wilkins, Sylvie Roke, Michele Ceriotti

摘要:

长期以来,人们一直认为水和其他大块分子液体的二次谐波散射实验对分子之间的相互作用不敏感。测量的强度通常被认为是由单个分子引起的非相干散射引起的。本文介绍了一种直接从原子计算机模拟中计算分子液体二次谐波散射图样的方法,该方法考虑了相干项。我们将这种方法应用于液态水的大尺度分子动力学模拟,在那里我们表明纳秒二次谐波散射实验包含由< 1 nm的长度尺度上的径向和角相关引起的相干贡献,比最近假设的要短得多(Shelton,D. P.J.Chem.Phys.2014,141)。通过将来自模拟的结构相关性与实验数据相结合(Shelton,D. P.J.Chem.Phys.2014,141),我们还可以在液相中提取有效的分子超极化率。这项工作表明,二次谐波散射实验和原子模拟可以协同使用,以调查复杂的液体,溶液和生物膜的结构,包括内在的分子间的相关性。

英文摘要:

Second-harmonic scattering experiments of water and other bulk molecular liquids have long been assumed to be insensitive to interactions between the molecules. The measured intensity is generally thought to arise from incoherent scattering due to individual molecules. We introduce a method to compute the second-harmonic scattering pattern of molecular liquids directly from atomistic computer simulations, which takes into account the coherent terms. We apply this approach to large-scale molecular dynamics simulations of liquid water, where we show that nanosecond second-harmonic scattering experiments contain a coherent contribution arising from radial and angular correlations on a length scale of < 1 nm, much shorter than had been recently hypothesized (Shelton, D. P. J. Chem. Phys. 2014, 141). By combining structural correlations from simulations with experimental data (Shelton, D. P. J. Chem. Phys. 2014, 141), we can also extract an effective molecular hyperpolarizability in the liquid phase. This work demonstrates that second-harmonic scattering experiments and atomistic simulations can be used in synergy to investigate the structure of complex liquids, solutions, and biomembranes, including the intrinsic intermolecular correlations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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