The photodouble ionization of water at about 32eV excess energy has been investigated both experimentally and theoretically. In an energy and angular resolved photoelectron–photoelectron coincidence experiment, the two photoelectrons in unequal energy sharing (25 and 7eV) condition, have been detected in a plane perpendicular to the propagation direction of the linearly polarized radiation. The measured angular distributions have been compared with, molecular orientation averaged, triple differential cross sections calculated with a recently developed theoretical model (Randazzo etal 2020 Phys. Rev. A 101 033407). The model uses separable products of orbitals as initial electronic state of the water molecule taken as a two-electron target and describes accurately the correlated two electron continuum. The combination of calculated cross sections corresponding to different dication states capture most of the measured features in terms of the evolution of both the shape and the intensity as a function of the faster electron direction which is set at 0, 30 and 60 with respect to the polarization vector of the incident radiation. A detailed analysis in terms of the different dication states as well as of the partial wave contributions to the electron pair wave function sheds light on the origin of such features.

已经通过实验和理论研究了水在大约32eV过量能量下的光双电离。在能量和角分辨光电子-光电子重合实验中，在垂直于线性偏振辐射传播方向的平面上检测到两个能量分配不平等（25和7eV）的光电子。已将测得的角分布与分子取向平均，使用最新开发的理论模型（Randazzo etal 2020 Phys.Re.A 101033407）。该模型使用可分离的轨道积作为水分子的初始电子态，并将其作为双电子目标，并准确地描述了相关的两个电子连续体。根据形状和强度的演变，对应于不同指示状态的计算横截面的组合捕获了大多数测量特征，而形状和强度是相对于较快电子方向的函数，相对于电子方向设置为0、30和60。入射辐射的极化矢量。根据不同的指示状态以及对电子对波函数的部分波贡献进行的详细分析揭示了此类特征的起源。