We extracted the molecular-frame elastic differential cross sections (MFDCSs) for electrons scattering from ${\mathrm{N}}_2^{+}$ based on elliptical laser-induced electron diffraction (ELIED), wherein the structural evolution is initialized by the same tunneling ionization and probed by incident angle-resolved laser-induced electron diffraction imaging. To establish ELIED, an intuitive interpretation of the ellipticity-dependent rescattering electron momentum distributions was first provided by analyzing the transverse momentum distribution. It was shown that the incident angle of the laser-induced returning electrons could be tuned within 20° by varying the ellipticity and handedness of the driving laser pulses. Accordingly, the incident angle-resolved DCSs of returning electrons for spherically symmetric targets (${\mathrm{Xe}}^{+}$ and ${\mathrm{Ar}}^{+}$) were successfully extracted as a proof-of-principle for ELIED. The MFDCSs for ${\mathrm{N}}_2^{+}$ were experimentally obtained at incident angles of 4° and 7°, which were well reproduced by the simulations. The ELIED approach is the only successful method so far for obtaining incident angle-resolved ionic MFDCS, which provides a new sensitive observable for the transient structure retrieval of ${\mathrm{N}}_2^{+}$. Our results suggest that the ELIED has the potential to extract the structural tomographic information of polyatomic molecules with femtosecond and subangstrom spatiotemporal resolutions that can enable the visualization of the nuclear motions in complex chemical reactions as well as chiral recognition.

中文翻译：

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基于椭圆激光诱导电子衍射的分子框架电子-离子差分散射截面提取


我们提取了电子散射的分子框架弹性微分截面（MFDCS） ${\mathrm{N}}_2^{+}$ 基于椭圆激光诱导电子衍射（ELIED），其中结构演化由相同的隧道电离初始化，并通过入射角分辨激光诱导电子衍射成像进行探测。为了建立 ELIED，首先通过分析横向动量分布来提供对椭圆率相关的重散射电子动量分布的直观解释。结果表明，通过改变驱动激光脉冲的椭圆率和旋向性，可以在 20° 范围内调整激光诱导返回电子的入射角。因此，球对称目标的返回电子的入射角分辨 DCS（ ${\mathrm{Xe}}^{+}$ 和 ${\mathrm{Ar}}^{+}$ ）被成功提取作为 ELIED 的原理验证。 MFDCS 用于 ${\mathrm{N}}_2^{+}$ 是在 4° 和 7° 入射角下通过实验获得的，并且通过模拟得到了很好的再现。 ELIED方法是迄今为止获得入射角分辨离子MFDCS的唯一成功方法，它为瞬态结构反演提供了一种新的灵敏可观测值。 ${\mathrm{N}}_2^{+}$ 。我们的结果表明，ELIED 有潜力以飞秒和亚埃时空分辨率提取多原子分子的结构断层扫描信息，从而实现复杂化学反应中核运动的可视化以及手性识别。