CNR-NANO, Via Campi 213/a, 41125 Modena, Italy.
Scuola Internazionale Superiore di Studi Avanzati (SISSA) and CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste, Italy.
J Chem Phys. 2018 Oct 21;149(15):154102. doi: 10.1063/1.5038864.
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 CH, CO, and N 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 planar complex.
角分辨光电子能谱允许人们在动量空间中可视化从沉积在衬底上的分子中减去的电子的概率权重图。这些图谱的解释通常依赖于通过密度泛函理论获得的单粒子轨道的傅里叶变换的平面波近似。在这里，我们提出了一种基于量子蒙特卡罗 (QMC) 的第一性原理多体方法，用于直接计算分子在动量空间中的准粒子波函数（也称为 Dyson 轨道）。这些相关的 QMC 图像与其单粒子对应物的比较突出了源于多体效应的特征。我们在 CH、CO 和 N 等线性分子上测试了 QMC 方法，这些分子只能看到小幅度的重新调制。然后，我们考虑了并五苯分子的情况，重点关注动量空间特征与实空间准粒子轨道之间的关系。最后，我们验证了金属平面复合物中存在的相关效应。
