Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland.
J Chem Phys. 2017 Mar 28;146(12):124306. doi: 10.1063/1.4977933.
We present a theoretical formalism for the calculation of attosecond delays in molecular photoionization. It is shown how delays relevant to one-photon-ionization, also known as Eisenbud-Wigner-Smith delays, can be obtained from the complex dipole matrix elements provided by molecular quantum scattering theory. These results are used to derive formulae for the delays measured by two-photon attosecond interferometry based on an attosecond pulse train and a dressing femtosecond infrared pulse. These effective delays are first expressed in the molecular frame where maximal information about the molecular photoionization dynamics is available. The effects of averaging over the emission direction of the electron and the molecular orientation are introduced analytically. We illustrate this general formalism for the case of two polyatomic molecules. NO serves as an example of a polar linear molecule characterized by complex photoionization dynamics resulting from the presence of molecular shape resonances. HO illustrates the case of a non-linear molecule with comparably simple photoionization dynamics resulting from a flat continuum. Our theory establishes the foundation for interpreting measurements of the photoionization dynamics of all molecules by attosecond metrology.
我们提出了一种用于计算分子光电离中阿秒延迟的理论形式。结果表明，如何从分子量子散射理论提供的复偶极矩矩阵元中获得与单光子电离（也称为 Eisenbud-Wigner-Smith 延迟）相关的延迟。这些结果用于推导基于阿秒脉冲串和调制飞秒红外脉冲的双光子阿秒干涉测量中测量的延迟的公式。这些有效延迟首先在分子框架中表示，在该框架中可以获得关于分子光电离动力学的最大信息。通过电子发射方向和分子取向的平均引入了分析表达式。我们以两个多原子分子的情况说明了这个一般的形式。NO 作为一个具有复杂光电离动力学的极性线性分子的例子，其动力学源于分子形状共振的存在。HO 说明了一个具有相对简单光电离动力学的非线性分子的情况，这是由于平坦的连续体。我们的理论为通过阿秒计量学测量所有分子的光电离动力学建立了基础。
