Spectroscopic analysis in molecular simulations with discretized Wiener-Khinchin theorem for Fourier-Laplace transformation
Spectroscopic analysis in molecular simulations with discretized Wiener-Khinchin theorem for Fourier-Laplace transformation
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使用傅里叶-拉普拉斯变换的离散维纳-辛钦定理进行分子模拟中的光谱分析
DOI：
10.1103/physreve.102.063302
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发表时间：
2020
影响因子：
2.4
通讯作者：
Yamamoto Takashi
中科院分区：
文献类型：
--
作者：
Koyama Akira;Nicholson David A.;Andreev Marat;Rutledge Gregory C.;Fukao Koji;Yamamoto Takashi
傅里叶-拉普拉斯变换的维纳-欣钦定理（Wiener-Khinchin theorem for the Fourier-Laplace transformation，WKT-FLT）提供了一种鲁棒的方法来获得任意时域松弛函数（或自相关函数）的单边傅里叶变换。此外，通过将实时算法与WKT-FLT相结合，在宽频率范围内对各种复杂光谱数据的数值计算变得更加有效。然而，离散化的WKT-FLT方程，简单地通过用离散求和替换积分获得，总是在频域松弛函数中产生两个伪影。此外，在从松弛函数转换的频域响应函数中，伪影变得更加明显。我们发现这些文物的来源，与离散化的WKT-FLT方程。考虑到这些来源，我们推导出离散WKT-FLT方程指定的频域松弛和响应函数与文物删除。使用的离散WKT-FLT方程与飞行算法的流程图说明。文中还给出了各向同性无定形聚乙烯中与波矢相关的动态磁化率和正构烷烃晶体中取向矢量的频域响应函数的应用实例。
The Wiener-Khinchin theorem for the Fourier-Laplace transformation (WKT-FLT) provides a robust method to obtain the single-side Fourier transforms of arbitrary time-domain relaxation functions (or autocorrelation functions). Moreover, by combining an on-the-fly algorithm with the WKT-FLT, the numerical calculations of various complex spectroscopic data in a wide frequency range become significantly more efficient. However, the discretized WKT-FLT equation, obtained simply by replacing the integrations with the discrete summations, always produces two artifacts in the frequency-domain relaxation function. In addition, the artifacts become more apparent in the frequency-domain response function converted from the relaxation function. We find the sources of these artifacts that are associated with the discretization of the WKT-FLT equation. Taking these sources into account, we derive discretized WKT-FLT equations designated for both the frequency-domain relaxation and response functions with the artifacts removed. The use of the discretized WKT-FLT equations with the on-the-fly algorithm is illustrated by a flow chart. We also give application examples for the wave-vector-dependent dynamic susceptibility in an isotropic amorphous polyethylene and the frequency-domain response functions of the orientation vectors in an-alkane crystal.