Modeling X‑ray Photoelectron Spectroscopy of Macromolecules Using GW

We propose a simple additive approach to simulate X-ray photoelectron spectra (XPS) of macromolecules based on the GW method. Single-shot GW (G0W0) is a promising technique to compute accurate core–electron binding energies (BEs). However, its application to large molecules is still unfeasible. To circumvent the computational cost of G0W0, we break the macromolecule into tractable building blocks, such as isolated monomers, and sum up the theoretical spectra of each component, weighted by their molar ratio. In this work, we provide a first proof of concept by applying the method to four test polymers and one copolymer and show that it leads to an excellent agreement with experiments. The method could be used to retrieve the composition of unknown materials and study chemical reactions, by comparing the simulated spectra with experimental ones.本研究提出一种基于GW方法（GW method）模拟高分子X射线光电子能谱（X-ray photoelectron spectra, XPS）的简易加和式方案。单次GW（G0W0）是一种可精准计算核心电子结合能（binding energies, BEs）的极具潜力的技术，但其应用于大型分子仍不具备可行性。为规避G0W0高昂的计算成本，我们将高分子拆解为易处理的结构基元（如孤立单体），并以各组分的摩尔比为权重，对其理论能谱进行加和。本工作通过将该方法应用于四种测试聚合物与一种共聚物，完成了首次概念验证，结果显示模拟能谱与实验结果具有极佳的吻合度。该方法可通过对比模拟能谱与实验能谱，实现未知材料的组分反演，并可用于化学反应的相关研究。