We present a general computational protocol for the evaluation of extensive molecular response properties in complex environments within a polarizable quantum embedding framework. The approach extends multilevel density functional theory (MLDFT) to response theory by formulating the coupled-perturbed Kohn-Sham (CPKS) equations for the MLDFT Hamiltonian. The method is further coupled to an additional polarizable molecular mechanics layer based on the fluctuating-charge (FQ) force field, which allows an accurate yet computationally efficient description of long-range interactions. We apply this new protocol to compute static and frequency-dependent linear polarizabilities and first hyperpolarizabilities of para-nitroaniline (PNA) in 1,4-dioxane and 3-hydroxybenzoic acid (HBA) in aqueous solution. The framework enables physicochemical insight into solute-solvent interactions by disentangling the competing roles of electrostatics, mutual polarization, and quantum confinement (Pauli repulsion). The results match available experiments, demonstrating the reliability and robustness of the proposed approach and providing a viable route for response properties within quantum embedding methods.
Critical point search and linear response theory for computing electronic excitation energies of molecular systems. Part I: General framework, application to Hartree-Fock and DFT
CERMICS, Ecole des Ponts - Institut Polytechnique de Paris and Inria(巴黎路桥学校-巴黎理工学院计算数学与控制系统中心及法国国家信息与自动化研究所)
Computing X-ray absorption spectra from linear-response particles atop optimized holes
状态特定轨道优化密度泛函理论(OO-DFT)方法如限制性开壳层Kohn-Sham(ROKS)方法可以半定量地预测闭壳层分子的X射线吸收光谱。然而,OO-DFT方法要求每个状态被单独优化。在这项工作中,我们提出了一种方法来产生一个近似的核心激发态密度使用的ROKS能量分析,这是能够提供合理的准确性,而不需要特定的状态优化。这是通过完全优化的核心-空穴通过核心电离状态,然后通过使用电子添加配置相互作用单打(EA-CIS),以获得粒子的水平。这种混合方法可以被看作是静态交换(STEX)方法的DFT推广,并可以通过使用PBE和OLYP等局部泛函来获得C-F的K边的$\sim 0.6$ eV RMS误差。这种ROKS(STEX)方法也可以用来识别重要的转变,为全OO ROKS处理,因此可以帮助减少计算成本,获得OO-DFT质量的频谱。因此,ROKS(STEX)似乎是一种有效的预测X射线吸收光谱的有用技术。
Dielectric response of confined water films: Insights from classical DFT
我们重新审视的问题,高极性的液体,如水的介电响应的限制在两个墙壁之间使用一个简单的双变量密度泛函理论,涉及数量和极化密度。在纵向极化的情况下,扰动场施加垂直的墙壁,我们表明,局部介电常数的概念,虽然在微观层面上定义不清,是有意义的,当一个粗粒化的典型尺寸的颗粒被引入。该方法使研究各种厚度的薄液体膜的有效介电响应与最近的实验[Fumagalli et al.,Science,2018,360,1339-1342],并讨论界面介电常数的概念成为可能。我们认为,所观察到的性能作为板尺寸的函数,特别是非常低的介电常数的顺序为2-3测量的1 nm厚的薄板不突出任何特殊的性质的水,但可以恢复为一个通用的极性溶剂具有类似的粒径和相同的高介电常数。关于横向极化的情况下,扰动场是平行的墙壁,相关的有效介电常数作为板尺寸的函数达到批量样的值在更短的宽度比在纵向的情况下。
Ab initio density functional theory approach to warm dense hydrogen: from density response to electronic correlations
Center for Advanced Systems Understanding (CASUS)(高级系统理解中心);College of Physics, Jilin University(吉林大学物理学院);State Key Laboratory of High Pressure and Superhard Materials, Jilin University(吉林大学高压与超硬材料国家重点实验室);International Center of Future Science, Jilin University(吉林大学未来科学国际中心)
Benchmarking and contrasting exchange-correlation functional differences in response to static correlation in unrestricted Kohn-Sham and a hybrid 1-electron reduced density matrix functional theory