Department of Chemistry, The University of Memphis, Memphis, TN, 38152, USA.
Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Phys Chem Chem Phys. 2022 Jun 22;24(24):14680-14691. doi: 10.1039/d2cp01132h.
The emergence of state-of-the-art X-ray light sources has paved the way for novel spectroscopies that take advantage of their atomic specificity to shed light on fundamental physical, chemical, and biological processes both in the static and time domains. The success of these experiments hinges on the ability to interpret and predict core-level spectra, which has opened avenues for theory to play a key role. Over the last two decades, linear-response time-dependent density functional theory (LR-TDDFT), despite various theoretical challenges, has become a computationally attractive and versatile framework to study excited-state spectra including X-ray spectroscopies. In this context, we focus our discussion on LR-TDDFT approaches for the computation of X-ray Near-Edge Structure (XANES), Valence-to-Core X-ray Emission (VtC-XES), and Resonant Inelastic X-ray Scattering (RIXS) spectroscopies in molecular systems with an emphasis on Gaussian basis set implementations. We illustrate these approaches with applications and provide a brief outlook of possible new directions.
最先进的 X 射线光源的出现为新型光谱学铺平了道路，这些光谱学利用其原子特异性来揭示静态和动态领域中的基本物理、化学和生物过程。这些实验的成功取决于解释和预测芯能级谱的能力，这为理论发挥关键作用开辟了道路。在过去的二十年中，线性响应含时密度泛函理论（LR-TDDFT）尽管存在各种理论挑战，但已成为研究包括 X 射线光谱学在内的激发态光谱的一种具有吸引力和多功能的计算框架。在这种情况下，我们专注于 LR-TDDFT 方法在分子系统中计算 X 射线近边结构（XANES）、价壳层到芯 X 射线发射（VtC-XES）和共振非弹性 X 射线散射（RIXS）光谱的应用，重点是高斯基组的实现。我们用应用实例来说明这些方法，并简要展望可能的新方向。
