一种具有恒定势边界条件的嵌入方法
An embedding method with constant potential boundary conditions
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中文总结 AI 辅助
本研究提出了带恒定势边界条件的量子化学团簇嵌入自洽场框架，推导了单粒子密度矩阵更新的解析式，经应用验证可准确再现扩展系统响应，为电化学量子嵌入方法奠定基础。
中文摘要 AI 辅助
我们提出了一种自洽场框架，用于处理带有恒定势边界条件的有限嵌入量子化学团簇。该耦合通过能量无关的自能实现，该自能通常在宽禁带近似下用于量子输运计算。从相应的非平衡格林函数形式出发，我们推导了单粒子密度矩阵更新的解析表达式，该表达式可融入常规的Hartree–Fock（哈特里-福克）方法和密度泛函理论。所得的非厄米自洽场方程采用改进的Pulay型混合方案求解。对准周期氢环的应用表明，通过优化自能耦合的有限片段能准确再现扩展系统的极化响应；而对锂团簇的计算则捕捉到了开放边界条件下的金属电荷转移和分数占据。该框架为有限量子化学团簇建立了实用的巨正则边界条件，并为电化学系统的量子嵌入方法奠定了方法学基础。
英文摘要
We present a self-consistent field framework for finite embedded quantum-chemical clusters with constant potential boundary conditions. The coupling is realized through an energy-independent self-energy commonly employed in quantum-transport calculations within the wide-band approximation. Starting from the corresponding non-equilibrium Green's function formalism, we derive an analytic expression for the one-particle density matrix update that can be incorporated into conventional Hartree--Fock and density functional theory. The resulting non-Hermitian self-consistent field equations are solved using adapted Pulay-type mixing schemes. Applications to a quasi-periodic hydrogen ring demonstrate that a finite fragment coupled through an optimized self-energy accurately reproduces the polarization response of the extended system, while calculations on a lithium cluster capture metallic charge transfer and fractional occupations under open-boundary conditions. The proposed framework establishes practical grand-canonical boundary conditions for finite quantum-chemical clusters and lays the methodological foundation for quantum embedding methods for electrochemical systems.
