The optimized effective potential (OEP) approach has so far mainly been used in benchmark studies and for the evaluation of band gaps. In this work, we extend the application of the OEP by determining the analytical ionic forces within the plane-wave and pseudopotential framework. It is first shown that, due to the constrained optimization inherent to the OEP approach, an extra term needs to be added to the standard Hellmann-Feynman expression for the forces, whenever nonlocal pseudopotentials are employed. Computing this term for functionals based on Hartree-Fock and the hybrid PBE0 functional yields forces with excellent numerical accuracy. Furthermore, results for equilibrium geometries and vibrational frequencies on a set of molecules and solids confirm that the local exchange OEP is able to reproduce results obtained with the nonlocal exchange potential. Our work opens up the possibility to study lattice dynamics using advanced orbital functionals for describing exchange and correlation effects.
Calculating DMFT forces in ab-initio ultrasoft pseudopotential formalism
在本文中，我们展示了如何计算分析原子力的自洽密度泛函理论+动力学平均场论（DFT+DMFT）方法的情况下，使用超软或范数守恒的赝势。我们将展示如何处理赝势形式主义内产生的非局部投影项，并规避科恩-沙姆特征向量的非正交性问题。我们的方法是，在原则上，独立的DMFT求解器，并在这里进行了测试与哈伯德我求解器。我们基准我们的形式主义通过比较对Ce $_{2}$ O $_{3}$和PrO $_2$的总自由能的数值微分计算的力，以及通过比较对数值积分的分析力的能量分布。
Pseudopotentials for Orbital-Free DFT: Capturing Nonlocality and Correcting Functional Approximants
Rutgers University（罗格斯大学）；University of Ibadan（伊巴丹大学）；Jilin University（吉林大学）；East African Institute for Fundamental Research (EAIFR), University of Rwanda（卢旺达大学东非基础研究院）；Lira University（利拉大学）
Faster Exact Exchange for Solids via occ-RI-K: Application to Combinatorially Optimized Range-Separated Hybrid Functionals for Simple Solids with Pseudopotentials Near the Basis Set Limit
In this work, we developed and showcased the occ-RI-K algorithm to compute the exact exchange contribution in density functional calculations of solids near the basis set limit. Within the gaussian planewave (GPW) density fitting, our algorithm achieves a 1-2 orders of magnitude speedup compared to conventional GPW algorithms. Since our algorithm is well-suited for simulations with large basis sets, we applied it to 12 hybrid density functionals with pseudopotentials and a large uncontracted basis set to assess their performance on band gaps of 25 simple solids near the basis set limit. The la…
Plane wave/pseudopotential implementation of excited state gradients in density functional linear response theory: a new route via implicit differentiation
Simulation of crack propagation in alumina with ab-initio based polarizable force field
我们提出了一个有效的原子相互作用势的结晶α-Al 2 O 3产生的程序potfit。静电相互作用的沃尔夫直接，成对求和方法与球形截断。利用Tangney-Scandolo原子间力场方法计算了氧原子的极化率。势被优化以再现在松弛和应变配置以及Al 2 O3的{0001}、{10-10}和{11-20}表面中的力、能量和应力。力场生成的细节，并证明其有效性。我们应用开发的潜力，调查裂纹扩展α-Al 2 O 3单晶。
