Borràs Vicent J, González-Vázquez Jesús, Argenti Luca, Martín Fernando
Departamento de Química, Universidad Autónoma de Madrid, Módulo 13, 28049 Madrid, Spain.
Department of Physics and CREOL, University of Central Florida, Orlando, Florida 32186, United States.
J Chem Theory Comput. 2021 Oct 12;17(10):6330-6339. doi: 10.1021/acs.jctc.1c00480. Epub 2021 Sep 16.
The advent of ultrashort XUV pulses is pushing for the development of accurate theoretical calculations to describe ionization of molecules in regions where electron correlation plays a significant role. Here, we present an extension of the XCHEM methodology to evaluate laboratory- and molecular-frame photoelectron angular distributions in the region where Feshbach resonances are expected to appear. The performance of the method is demonstrated in the CO molecule, for which information on Feshbach resonances is very scarce. We show that photoelectron angular distributions are dramatically affected by the presence of resonances, to the point that they can completely reverse the preferred electron emission direction observed in direct nonresonant photoionization. This is the consequence of significant changes in the electronic structure of the molecule when resonances decay, an effect that is mostly driven by electron correlation in the ionization continuum. The present methodology can thus be helpful for the interpretation of angularly resolved photoionization time delays in this and more complex molecules.
超短极紫外（XUV）脉冲的出现推动了精确理论计算的发展，以描述电子关联起重要作用区域中分子的电离过程。在此，我们展示了XCHEM方法的扩展，用于评估预期会出现费什巴赫共振区域中的实验室坐标系和分子坐标系光电子角分布。该方法的性能在CO分子中得到了验证，对于CO分子，费什巴赫共振的信息非常稀少。我们表明，光电子角分布会受到共振的显著影响，以至于它们可以完全反转在直接非共振光电离中观察到的优先电子发射方向。这是共振衰减时分子电子结构发生重大变化的结果，这种效应主要由电离连续体中的电子关联驱动。因此，本方法有助于解释该分子以及更复杂分子中的角分辨光电离时间延迟。
