Computational and Quantum Chemistry
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A group dedicated to everything about theoretical and computational/quantum chemistry.
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🚀 CP2K v2026.2 released
Main new features:
• DFT+U, Löwdin analysis and Harris functional with k-points
• k-point symmetry reduction and wavefunction extrapolation
• ACE acceleration for HFX/ADMM
• Broadened DOS/PDOS with k-point projections
• Brownian-chain molecular dynamics for path integrals
• Fixed-volume cell optimization
• Improved NEB output and CIF/EXTXYZ structure export
• CUDA-accelerated Hartree–Fock exchange via libGint
• New LibFCI active-space solver
• openPMD output support
Release notes and downloads:
https://github.com/cp2k/cp2k/releases/tag/v2026.2
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OpenClatura: an open-source structure-to-name tool

OpenClatura is a new open-source Python package for generating systematic chemical names from SMILES.

Developed by Adrian Mirza, Kevin Maik Jablonka, and Rostislav at LAMA Lab, it aims to provide an open and inspectable alternative to structure-to-name tools such as ChemDraw’s naming functionality.

OpenClatura uses a rule-based approach, exposes intermediate naming decisions, and supports optional OPSIN round-trip checks.

The project is currently in beta, and feedback is very welcome, especially on:

• installation or compatibility issues
• difficult or unusual molecules
• unexpected names or failed cases
• possible applications and integrations

Install from PyPI:

pip install openclatura

Try it from the command line:

openclatura name "CC(=O)Nc1ccccc1"

GitHub and documentation:
https://github.com/lamalab-org/openclatura

Issues:
https://github.com/lamalab-org/openclatura/issues

Even a quick installation check or one difficult test molecule would help.
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🔬 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
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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.
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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
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This is an image. The link is just below!
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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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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.
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