Computational and Quantum Chemistry

PyFock - An efficient and fully parallelized pure python DFT and electronic structure code with GPU acceleration through just-in-time compilation https://pyfock.bragitoff.com/ Read the paper: https://pubs.acs.org/jpcafh/article/doi/10.1021/acs.jpca.6c03727/5298372/PyFock-A-Just-In-Time-Compiled-Gaussian-Basis-DFT

OPEN ACCESS https://www.nature.com/articles/s41467-026-77099-7?utm_source=chatgpt.com

ORCA (FACCTs & Max-Planck-Institut für Kohlenforschung) is a powerful quantum chemistry engine, valued for its wide range of methods, outstanding efficiency, and robustness. But modern computational workflows and Agentic AI need more than scientific breadth. They also need software that can be controlled, interpreted, and integrated programmatically. At this point, we can say: ORCA is ready! Over the past few years, ORCA's ecosystem has evolved rapidly, introducing key features such as: Machine-readable JSON output, providing structured results that can be used directly by scripts, workflow engines, and AI agents. The ORCA Python Interface (OPI), providing Python-native control for building and automating computational workflows. And extensive online documentation and tutorials, providing the knowledge layer that helps users and AI agents understand ORCA's capabilities, select and configure methods correctly, interpret workflows, and make informed decisions. All of this makes ORCA not only a powerful quantum chemistry program, but also a strong foundation for automated and agentic computational science. ORCA json manual: https://lnkd.in/eBXMFaVX OPI docs: https://lnkd.in/ePfDNhqa ORCA manual: https://lnkd.in/dzPaAMtJ ORCA tutorials: https://lnkd.in/dfGmE4wk #ORCA #QuantumChemistry #ComputationalChemistry #ScientificCompu

Fun Fact of the Day The “negative frequency” printed for a transition state is not really a vibration with a negative physical frequency. At a first-order saddle point, the Hessian has one negative eigenvalue; because the harmonic relation is effectively ω² ∝ curvature, that mode has an imaginary ω, and quantum-chemistry programs conventionally display it as a negative wavenumber. That is why the important transition-state check is not merely “one negative number,” but whether the corresponding eigenvector actually follows the intended reaction coordinate.

open access https://www.nature.com/articles/s41566-026-01946-8?utm_source=bluesky&utm_medium=social&utm_campaign=nphoton

Fun Fact of the Day One hartree is such a large molecular energy unit that, when expressed as the equivalent thermal scale Eₕ/k_B, it corresponds to approximately 315,775 K. That does not mean a one-hartree electronic excitation corresponds physically to heating a molecule to 315,775 K; it is simply the temperature for which k_BT equals one hartree. NIST tabulates the hartree–kelvin relationship among its CODATA energy conversions. For comparison, chemically important energy differences are usually tiny fractions of Eₕ: 1 kcal mol⁻¹ is only about 0.00159 Eₕ.

xyzrender: Publication-quality molecular graphics. Render molecular structures as publication-quality SVG, PNG, PDF, and animated GIF from XYZ, mol/SDF, MOL2, PDB, SMILES, CIF, SHELXL, cube files, quantum chemistry input or output — from the command line or from Python/Jupyter. xyzrender turns molecular structures into clean vector SVG graphics — plus PNG, PDF, and animated GIF — ready for papers, presentations, and supporting information. It reads XYZ, mol/SDF, MOL2, PDB, SMILES, CIF, SHELXL, cube files, and QM input/output files from Gaussian, ORCA, NWChem, Q-Chem, Psi4, MOPAC, GAMESS, Turbomole, and periodic codes (VASP, Quantum ESPRESSO, SIESTA, ABINIT, CP2K). The SVG rendering approach is built on and inspired by xyz2svg (https://github.com/briling/xyz2svg) by Ksenia Briling @briling (https://github.com/briling). https://github.com/aligfellow/xyzrender

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⚛️ Quantum ESPRESSO 7.6 has been released! Some notable additions in this release: • EPW 6.1, including: GPU offloading via CUDA, OpenACC and OpenMP Two-level parallelisation using images and pools, on both coarse and fine grids Support for DFPT+U Support for LSDA • NLCC support for norm-conserving pseudopotentials with meta-GGA functionals • Support for ONCV pseudopotentials with r²SCAN, using a model atomic kinetic-energy density • New vdW-DF3-mc van der Waals functional, aimed at molecular crystals • Improvements to PP/epsilon and eps_calc, including symmetry and nonlocal-pseudopotential contributions and support for USPP and PAW • BEEF-vdW exposed through LibXC as BEEF_LXC • Performance optimisation and GPU porting of lr_addusddens • Autoconf now supports out-of-source builds There are also several bug fixes affecting meta-GGA stresses, Raman coefficients, phonons, TDDFPT restarts, ELF and pw2wannier90. 🔗 Release notes and download: https://gitlab.com/QEF/q-e/-/releases/qe-7.6

Fun Fact of the Day For 50 electrons distributed among 100 spin orbitals, the full determinant space contains C(100,50) = 100,891,344,545,564,193,334,812,497,256 determinants, approximately 1.01 × 10²⁹. The corresponding one-particle reduced density matrix contains only 100² = 10,000 elements. That compression is enormous, but the 1RDM alone does not uniquely specify a general interacting wavefunction without an exact density-matrix functional.

🔬 PySCF v2.14.0 has been released The new version substantially expands PySCF’s capabilities for many-body electronic structure, multireference calculations, periodic systems, and relativistic methods. Main additions: • Molecular Bethe–Salpeter equation (BSE) calculations, supporting restricted and unrestricted GW references • New G₀W₀, self-consistent GW, and periodic GW developments, with improved CPU and memory efficiency • Spin-restricted and unrestricted k-point RPA, including periodic calculations with smeared occupations • Implementation of the RCCSDT(Q) correction for high-order coupled-cluster calculations • Spin–orbit-coupling Hamiltonian for GCCSD, together with support for complex GCCSD orbitals • Analytic CASCI gradients using UHF, RKS, or UKS orbitals • New MC26 and COF26 on-top functionals • CABS singles correction and new q-vSZP basis-set/ECP variants • Self-consistent dipole corrections for slab and two-dimensional periodic systems • Pipek–Mezey Wannier functions and Wannier interpolation for periodic k-point calculations Other improvements include: • Better Windows compatibility • HOMO–LUMO gap reporting in SCF output • Configurable ωB97X-D4 parameters • Improved numerical stability in periodic RPA • Reduced memory usage in PCM gradients and periodic density fitting • Corrections affecting X2C, meta-GGA derivatives, UKS Hessians, ghost atoms, and Basis Set Exchange loading Upgrade with: pip install --upgrade pyscf 📋 Full release notes: https://github.com/pyscf/pyscf/releases/tag/v2.14.0 📚 Documentation: https://pyscf.org 📦 PyPI package: https://pypi.org/project/pyscf/ #PySCF #QuantumChemistry #ComputationalChemistry