通过非正交展开解决实时时相关轨道传播方法中的峰移效应
Resolving Peak Shifting Effects in Real-Time Time-Dependent Orbital Propagation Methods Through Nonorthogonal Expansions
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中文总结 AI 辅助
本文开发RT-TD NOMCSCF方法，揭示单/多参考极限下峰移的共同起源，通过抑制内部空间态平均效应解决峰移问题，实现更准确的超快过程模拟。
中文摘要 AI 辅助
自洽场实时电子结构方法是模拟超快过程的有力手段，但预测的跃迁能量存在系统误差，即峰移效应，这使得与实验的直接对比变得模糊。尽管该效应已在单参考方法中得到研究，但适用于多组态方法的通用理解仍未解决。本文中，我们开发了实时非正交多组态自洽场（RT-TD NOMCSCF）形式，其中独立传播的轨道集生成紧凑的非正交波函数。该方法为非线性实时电子结构理论建立了统一框架，我们利用该框架揭示了单参考和多参考极限下峰移的共同起源。通过该框架，我们证明峰移并非仅源于内部空间基组上的态平均效应，还源于可访问的外部组态空间。通过用独立传播的轨道集系统扩展内部空间，RT-TD NOMCSCF抑制了这种平均效应，恢复了正确的跃迁能量，并将固有峰移与传播误差导致的数值峰漂移区分开来。因此，这些进展建立了能更准确模拟超快过程的非线性实时电子结构方法。
英文摘要
Self-consistent field real-time electronic structure methods are a powerful approach for modeling ultrafast processes but suffer from systematic errors in predicted transition energies, commonly known as peak shifting, that obscure direct comparison with experiment. Although this effect has been explored in single reference methods, a general understanding that extends to multiconfigurational methods remains unresolved. Here, we develop a real-time nonorthogonal multiconfigurational self-consistent field (RT-TD NOMCSCF) formalism in which independently propagated orbital sets generate a compact, nonorthogonal wavefunction. The approach establishes a unified framework for nonlinear real-time electronic structure theories, which we use to reveal the common origin of peak shifting across single and multireference limits. Using this framework, we demonstrate that peak shifting does not arise exclusively from the effect of state averaging over the internal space basis, but also from the accessible external configurational space. By systematically expanding the internal space with independently propagated orbital sets, RT-TD NOMCSCF suppresses this aver- aging, recovers correct transition energies, and distinguishes intrinsic peak shifting from numerical peak drifting caused by propagation errors. Thus, these developments establish nonlinear real-time electronic structure methods that enables more accurate simulations of ultrafast processes.
