Angle-resolved photoemission spectroscopy allows one to visualize in momentum space the probability weight maps of electrons subtracted from molecules deposited on a substrate. The interpretation of these maps usually relies on the plane wave approximation through the Fourier transform of single particle orbitals obtained from density functional theory. Here we propose a first-principle many-body approach based on quantum Monte Carlo (QMC) to directly calculate the quasi-particle wave functions (also known as Dyson orbitals) of molecules in momentum space. The comparison between these correlated QMC images and their single particle counterpart highlights features that arise from many-body effects. We test the QMC approach on the linear C₂H₂, CO₂, and N₂ molecules, for which only small amplitude remodulations are visible. Then, we consider the case of the pentacene molecule, focusing on the relationship between the momentum space features and the real space quasi-particle orbital. Eventually, we verify the correlation effects present in the metal ${\text{CuCl}}_4^{2-}$ planar complex.

中文翻译：

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第一性原理量子蒙特卡洛的角分辨光发射光谱

角度分辨光发射光谱学使人们能够在动量空间中可视化从沉积在基板上的分子中减去的电子的概率权重图。这些图的解释通常依赖于通过从密度泛函理论获得的单粒子轨道的傅里叶变换进行的平面波逼近。在这里，我们提出一种基于量子蒙特卡洛（QMC）的第一性原理多体方法，以直接计算动量空间中分子的准粒子波函数（也称为戴森轨道）。这些相关的QMC图像与其单个粒子对应物之间的比较突出了多体效应产生的特征。我们在线性C ₂ H ₂，CO ₂和N上测试QMC方法_2个分子，仅能看到小幅度的调制。然后，我们考虑并五苯分子的情况，着重于动量空间特征与实际空间准粒子轨道之间的关系。最终，我们验证了金属中存在的相关效应${\text{氯化铜}}_4^{\mathrm{2个}-}$ 平面复合体。