Two-dimensional retrieval methods for ultrafast imaging of molecular structure using laser-induced electron diffraction.
Two-dimensional retrieval methods for ultrafast imaging of molecular structure using laser-induced electron diffraction.
复制标题
使用激光诱导电子衍射对分子结构进行超快成像的二维检索方法。
DOI：
10.1063/5.0064761
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
C. Lin
中科院分区：
文献类型：
--
作者：
Su;J. Daněk;C. Blaga;L. DiMauro;J. Biegert;C. Lin
基于电子衍射的分子结构恢复被提出用来确定亚埃、空间和飞秒时间分辨率的分子的原子位置。鉴于它在小分子体系上的成功，在这项工作中，我们指出结构提取的准确性受到所有分子体系动量空间中广泛实验数据可用性的限制。为了缓解这些限制，对于激光诱导的电子衍射，我们在实验室框架下使用二维(能量和角度)电子动量谱对一些小分子系统进行了恢复，这是以前用一维方法研究的。与传统的单能量或单角度分析相比，我们的二维分析方法有效地扩展了测量数据的动量范围。除了利用2D数据外，还开发了两种互补的方法来对反演结果进行一致性检验。我们的方法的2D性质也提供了一种估计检索误差的方法，这是以前从未探索过的。与以前的实验结果相比，我们的发现表明我们的2D方法优于传统的1D方法。对于难以获得隧穿电离率的大分子体系，我们估算了用各向同性模型代替考虑取向相关电离率的误差。
Molecular structural retrieval based on electron diffraction has been proposed to determine the atomic positions of molecules with sub-angstrom spatial and femtosecond temporal resolutions. Given its success on small molecular systems, in this work, we point out that the accuracy of structure retrieval is constrained by the availability of a wide range of experimental data in the momentum space in all molecular systems. To mitigate the limitations, for laser-induced electron diffraction, here we retrieve molecular structures using two-dimensional (energy and angle) electron momentum spectra in the laboratory frame for a number of small molecular systems, which have previously been studied with 1D methods. Compared to the conventional single-energy or single-angle analysis, our 2D methods effectively expand the momentum range of the measured data. Besides utilization of the 2D data, two complementary methods are developed for consistency check on the retrieved results. The 2D nature of our methods also offers a way of estimating the error from retrieval, which has never been explored before. Comparing with results from prior experiments, our findings show evidence that our 2D methods outperform the conventional 1D methods. Paving the way to the retrieval of large molecular systems, in which their tunneling ionization rates are challenging to obtain, we estimate the error of using the isotropic model in place of including the orientation-dependent ionization rate.