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这个实验室处于未激活状态 - 等待LabXing管理员的批准

Jian Liu Research Group(刘剑课题组)

简介

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Applications

● Nuclear Quantum Effects in Vibrational Spectroscopy

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Dipole Moment Vector (IR)

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Polarizability Tensor (Raman)

Understanding vibrational spectra (infrared (IR) and Raman spectra) at the atomistic level is important for the elucidation of dynamical processes in complex/large molecular systems. The correlation approach offers a bridge to connect the microscopic motion to the experimental spectrum. Because the dipole moment/polarizability (or its time derivative) is often a highly nonlinear function of coordinates or/and momenta, we have employed the linearized semiclassical initial value representation for quantum dynamical simulations of liquid water (and heavy water) under ambient conditions based on an ab initio based, flexible, polarizable model. Besides applying our new PIMD algorithms in the “middle” scheme, we have proposed a new technique (by using the finite difference along the direction of a related vector) to significantly reduce the computational cost for preparing the initial condition for the correlation function.

It is shown that quantum dynamical effects play a critical role in reproducing the peaks in the intermediate region between the librational and bending bands, those between the bending and stretching bands, and the double-peak in the stretching band in the experimental isotropic Raman spectrum. In contrast, quantum dynamical effects are important but less decisive in the anisotropic Raman spectrum. By selectively freezing either the intramolecular O-H stretching or H-O-H bending mode, we demonstrate that the peak in the intermediate region (2000-2400 cm-1) of the isotropic Raman spectrum arises from the interplay of the stretching and bending motions while a substantial part of the peak in the same intermediate region of the anisotropic Raman spectrum may be attributed to the combined motion of the bending and librational modes.

The relevant peer-reviewed papers are

  1. "Critical role of quantum dynamical effects in the Raman spectroscopy of liquid water"

    Xinzijian Liu, Jian Liu*

    Molecular Physics (2018)

    [Invited article for the special topic issue "Molecular Physics in China". Cover of the issue.]

    https://doi.org/10.1080/00268976.2018.1434907

    Note: In this article we show that quantum dynamical effects play a decisive role in reproducing the peaks in the intermediate region between the librational and bending bands, those between the bending and stretching bands, and the double-peak in the stretching band in the experimental isotropic Raman spectrum.

创建: Apr 09, 2018 | 15:31