PYSCF is a Python-based general-purpose electronic structure platform that both supports first-principles simulations of molecules and solids, as well as accelerates the development of new methodology and complex computational workflows. The present paper explains the design and philosophy behind PYSCF that enables it to meet these twin objectives. With several case studies, we show how users can easily implement their own methods using PYSCF as a development environment. We then summarize the capabilities of PYSCF for molecular and solid-state simulations. Finally, we describe the growing ecosystem of projects that use PYSCF across the domains of quantum chemistry, materials science, machine learning and quantum information science.

We have created a facial self-templated method to synthesize three distinct nanostructures, including the unique edge-cut Cu@Ni nanocubes, edgenotched Cu@Ni nanocubes, and mesoporous Cu−Ni nanocages by selective wet chemical etching method. Moreover, in the synthesis process, the corners of edgecut Cu@Ni nanocubes and mesoporous Cu−Ni nanocages can be etched to produce the highly catalytically active (111) facets. Impressively, compared to edge-notched Cu@Ni nanocubes and edge-cut Cu@Ni nanocubes, the Cu−Ni nanocages exhibit higher electrocatalytic activity in the hydrogen evolution reaction (HER) under alkaline conditions. When obtained overpotential is 140 mV, the current density can reach 10 mA cm −2 ; meanwhile, the corresponding Tafel slope is 79 mV dec −1 . Moreover, from the calculation results of density functional theory (DFT), it can be found that the reason why the activity of pure Ni is lower than that of Cu−Ni alloy is that the adsorption energy of the intermediate state (adsorbed H*) is too strong. Meanwhile the Gibbs free-energy (|ΔG H* |) of (111) facets is smaller than that of (100) facets, which brings more active sites or adsorbs more hydrogen.

Background Although the traditional bone augmentation technology can basically meet the clinical needs at present, the effect of bone augmentation in most cases is related to the experience of the operator. Propose This study commits to providing a digital solution for precise bone augmentation in the field of oral implantology. Materials and methods After collecting the data of patients' intraoral scanning and DICOM (digital imaging and communications in medicine), the implant position is digitally designed, and the alveolar bone is digitally augmented around the ideal implant position. On the premise of ensuring that the thickness of labial bone is 2 mm, and there is sufficient alveolar bone 3 to 4 mm apically from the ideal gingival margin for implant placing, we carry out excessive augmentation of 0.5 and 1 mm on the labial bone and alveolar crest, respectively, to compensate for possible bone resorption after 6 months. After 3D printing the reconstructed alveolar bone model, the titanium mesh is trimmed and preformed on the alveolar bone model. Outcomes are reported in terms of mean values (5%‐95% percentile values). Results Thirty implant sites have accepted this novel virtually designed alveolar bone augmentation. Before the second‐stage surgery, the average vertical bone gain was 2.48 mm (0.29‐6.32), the average horizontal bone gain was 4.11 mm (1.19‐8.74), the average height of the residual alveolar bone above the implant platform was 1.44 mm (0.59‐2.92), the average thickness of the labial bone width at the implant platform was 2.00 mm (0.93‐3.64), the average thickness of the labial bone width at 2 mm apically from the implant platform was 2.74 mm (1.40‐5.46). The virtual augmentation of each tooth position was 349.41 mm3 (165.70‐482.70), while the actual augmentation of each tooth position was 352.94 mm3 (159.24‐501.78), the accuracy of the final actual augmentation reached 95.82% (range from 88.53% to 99.15%). Conclusion This case series suggests that a virtually digital guided bone regeneration (GBR) workflow is precise and controllable. The practicality, safety and effectiveness of this procedure needs to be compared to other bone augmentation procedures in randomized controlled trials.

We describe the ground-and excited-state electronic structure of bulk MnO and NiO, two prototypical correlated electron materials, using coupled cluster theory with single and double excitations (CCSD). As a corollary, this work also reports the first implementation of unrestricted periodic ab initio equation-of motion CCSD. Starting from a Hartree-Fock reference, we find fundamental gaps of 3.46 eV and 4.83 eV for MnO and NiO respectively for the 16 unit supercell, slightly overestimated compared to experiment, although finite-size scaling suggests that the gap is more severely overestimated in the thermodynamic limit. From the character of the correlated electronic bands we find both MnO and NiO to lie in the intermediate Mott/charge-transfer insulator regime, although NiO appears as a charge transfer insulator when only the fundamental gap is considered. While the lowest quasiparticle excitations are of metal 3d and O 2p character in most of the Brillouin zone, near the Γ point, the lowest conduction band quasiparticles are of s character.Our study supports the potential of coupled cluster theory to provide high level many-body insights into correlated solids.

We describe a coupled cluster framework for coupled systems of electrons and phonons. Neutral and charged excitations are accessed via the equation-of-motion version of the theory. Benchmarks on the Hubbard-Holstein model allow us to assess the strengths and weaknesses of different coupled cluster approximations which generally perform well for weak to moderate coupling. Finally, we report progress towards an implementation for ab initio calculations on solids, and present some preliminary results on finite-size models of diamond. We also report the implementation of electron-phonon coupling matrix elements from crystalline Gaussian type orbitals (cGTO) within the PySCF program package.