AI 中文总结
该工作提出FHI-aims中全最小耦合的全电子实时TDDFT实现，保留矢势空间结构并支持周期系统，通过100 eV至5 keV基准验证，为X射线光-物质相互作用提供通用从头算方法。
AI 中文摘要
标准的实时含时密度泛函理论（RT-TDDFT）通过空间均匀（偶极）矢势将光与物质耦合，这种近似在X射线波段失效，因为该波段光子波长接近原子间尺度。我们提出了在FHI-aims中实现的全最小耦合的全电子、数值原子中心轨道实现，该实现保留了顺磁和抗磁耦合中矢势的空间结构，实现了倒空间分辨的电流诊断，并通过微扰光子动量边带耦合将传播扩展到周期系统，从而在光子波矢处恢复密度响应。从100 eV到5 keV的四个基准测试验证了该实现并检验了其适用范围。保留的光子动量在整个过程中具有物理重要性，从可测量的超越偶极修正到启用偶极极限中禁止的通道。在全电子基础上，该实现为跨分子、表面和固体的X射线光-物质相互作用的通用从头算处理奠定了基础。
英文摘要
Standard real-time time-dependent density functional theory (RT-TDDFT) couples light to matter through a spatially uniform (dipole) vector potential, an approximation that breaks down in the X-ray regime, where the photon wavelength approaches interatomic scales. We present an all-electron, numeric-atom-centered-orbital implementation of full minimal coupling in FHI-aims that retains the spatial structure of the vector potential in both the paramagnetic and diamagnetic couplings, implements a reciprocal-space-resolved current diagnostic, and extends the propagation to periodic systems through a perturbative photon-momentum sideband coupling that recovers the density response at the photon wavevector. Four benchmarks ranging in energy from 100 eV to 5 keV validate the implementation and exercise its reach. The retained photon momentum proves physically consequential throughout, from measurable beyond dipole corrections to the enabling of channels forbidden in the dipole limit. On an all-electron footing, the implementation lays the groundwork for a general ab initio treatment of X-ray light-matter interaction across molecules, surfaces, and solids.
