Bichromatic extreme-ultraviolet pulses from a seeded free-electron laser enable us to measure photoelectron angular distribution (PAD) as a function of the relative phase between the different wavelength components. The time-dependent multiconfiguration self-consistent-field (TD-MCSCF) methods are powerful multielectron computation methods to accurately simulate such photoionization dynamics from the first principles. Here, we propose a method to evaluate the amplitude and phase of each ionization path, which completely determines the photoionization processes, using TD-MCSCF simulation results. The idea is to exploit the capability of TD-MCSCF to calculate the partial wave amplitudes specified by the azimuthal and magnetic angular momenta (l, m) and the m-resolved PAD. The phases of the ionization paths as well as the amplitudes of the paths resulting in the same (l, m) are obtained through global fitting of the expression of the asymmetry parameters to the calculated m-resolved PAD, which depends on the relative phase of the bichromatic field. We apply the present method to ionization of Ne by combined fundamental and second-harmonic extreme ultraviolet pulses, demonstrating that the extracted amplitudes and phases excellently reproduce the asymmetry parameters.

来自种子自由电子激光器的双色极紫外脉冲使我们能够测量光电子角分布 (PAD) 作为不同波长分量之间相对相位的函数。瞬态多配置自洽场 (TD-MCSCF) 方法是强大的多电子计算方法，可以从第一原理准确模拟这种光电离动力学。在这里，我们提出了一种使用 TD-MCSCF 模拟结果来评估每个电离路径的幅度和相位的方法，该方法完全确定了光电离过程。这个想法是利用 TD-MCSCF 的能力来计算由方位角和磁角动量 ( l , m ) 和m- 已解决的 PAD。电离路径的相位以及导致相同 ( l , m )的路径的振幅是通过不对称参数的表达式与计算的m分辨 PAD 的全局拟合获得的，这取决于相对相位双色场。我们通过组合基波和二次谐波极紫外脉冲将本方法应用于 Ne 电离，证明提取的振幅和相位很好地再现了不对称参数。