论文标题
关于各向同性样品的光电角分布所揭示的分子信息
On the molecular information revealed by photoelectron angular distributions of isotropic samples
论文作者
论文摘要
我们提出了一种替代方法，以描述和分析光电角分布（PAD），这是在几乎没有光子吸收的情况下通过任意极化的电场吸收的情况。正如我们为单光子和两光子案例所证明的那样，这种方法揭示了PAD的$ b_ {l，m} $扩展系数中编码的分子框架信息，以特别清晰的方式。我们的方法不依赖散射波函数的显式部分波扩展，因此我们获得的表达式是根据光电偶极$ \ vec {d}（\ vec {k}）$来解释的，这是光电动量$ \ vec {k} $的函数。这提供了非常紧凑的表达式，可以揭示分子旋转不变性如何与设置（电场极化和检测器）旋转不变性。我们在有关紧张手性设置的同伴论文中严重依赖这种方法。在这里，我们将这种方法应用于单量电离，发现$ b_ {0,0} $仅取决于$ \ \ vec {d}（\ vec {k}）$的大小，$ b_ {1,0,0} $（non--Zero仅对chiral molecuules）仅对chiral molecules的组成;垂直于$ \ vec {k} $在倾向字段$ \ vec {b}（\ vec {k}）\ equiv i \ equec {d}^{*} {*}（\ vec {k}）\ times \ times \ times \ vec {d} $ vec {dempers $ vec {k’$ {k’= {k’沿$ \ vec {k} $的$ \ vec {d}（\ vec {k}）$的组件。我们还分析了增强的两光子案例，在其中我们表明$ b_ {0,0} $和$ b_ {1,0} $可以用有效拉伸的$ \ vec {d}（\ vec {k}）$写成，并列出$ b_ {1,0,0,0, $ b_ {$ b_} $ $ \ vec {b}（\ vec {k}）$在其三个向量球形谐波扩展系数中编码。
We propose an alternative approach to the description and analysis of photoelectron angular distributions (PADs) resulting from isotropic samples in the case of few-photon absorption via electric fields of arbitrary polarization. As we demonstrate for the one- and two-photon cases, this approach reveals the molecular frame information encoded in the $b_{l,m}$ expansion coefficients of the PAD in a particularly clear way. Our approach does not rely on explicit partial wave expansions of the scattering wave function and the expressions we obtain are therefore interpreted in terms of the vector field structure of the photoionization dipole $\vec{D}(\vec{k})$ as a function of the photoelectron momentum $\vec{k}$. This provides very compact expressions that reveal how molecular rotational invariants couple to the setup (electric field polarization and detectors) rotational invariants. We rely heavily on this approach in a companion paper on tensorial chiral setups. Here we apply this approach to one-photon ionization and find that while $b_{0,0}$ depends only on the magnitude of $\vec{D}(\vec{k})$, $b_{1,0}$ (non-zero for chiral molecules) is sensitive only to the components of $\vec{D}(\vec{k})$ perpendicular to $\vec{k}$ encoded in the propensity field $\vec{B}(\vec{k})\equiv i\vec{D}^{*}(\vec{k})\times\vec{D}(\vec{k})$, and $b_{2,0}$ is sensitive only to the the component of $\vec{D}(\vec{k})$ along $\vec{k}$. We also analyze the resonantly enhanced two-photon case where we show that $b_{0,0}$ and $b_{1,0}$ can be written in terms of an effectively stretched $\vec{D}(\vec{k})$, and that $b_{1,0}$ and $b_{3,0}$ reveal structural information of the field $\vec{B}(\vec{k})$ encoded in three of its vector spherical harmonic expansion coefficients.
