Quantum chemistry for molecules and solids.
A complete, self-contained suite built on its own C++17 engine — Hartree–Fock through DLPNO-CCSD(T), TD-DFT and CASSCF for molecules, and 1D/2D/3D periodic HF and Kohn–Sham DFT for solids. Every method implemented from the ground up, wrapped in its own queue, viewer and basis-set tooling.
The same engine, from a single molecule to an infinite crystal.
vibe-qc implements every method itself — no wrapped external QC program. Pick the stack; the Python front-end is identical.
Molecules
Gaussian-basis electronic structure from Hartree–Fock through coupled cluster and multireference, with analytic gradients and geometry optimization.
Solids
Crystalline-orbital HF and Kohn–Sham DFT in 1D, 2D and 3D with Monkhorst–Pack k-meshes and Ewald-summed Madelung energies.
Research-grade methods, honestly attributed.
Every basis set, functional and ECP carries its citation through to the run log — and every method is vibe-qc's own implementation, not a wrapper.
DLPNO local correlation
DLPNO-MP2 and the per-pair DLPNO-CCSD(T) solver bring gold-standard correlation to systems far larger than canonical scaling allows.
TD-DFT & spectra
Casida and Tamm–Dancoff for RHF/RKS/UHF/UKS, with natural transition orbitals and reconstructed UV/Vis spectra.
Analytic gradients
Production CASSCF and exact IC-CASPT2 analytic gradients, FD-tight to ~1e-7, driving geometry optimization.
Band structure & DOS
Full band paths and densities of states for periodic systems, with COOP/COHP bonding analysis in 1D, 2D and 3D.
Fast eigensolvers
Davidson, LOBPCG (3–12× faster), plus experimental Jacobi–Davidson and GPLHR — selectable with one solver= keyword.
Cyclic Cluster Model experimental
AICCM and SECCM — vibe-qc's own methods bring correlated wavefunction theory to periodic solids: a crystal treated as a finite cluster under exact translational symmetry. Unique to vibe-qc.
A quantum-chemistry suite, not a single program.
The engine sits at the center of a full toolchain — dispatch and track jobs, visualize results, and build your own basis sets, all under one project.
vibe-qc
Molecular and periodic electronic structure — its own C++17 implementation of every method it ships.
vq
Dispatch, schedule and track calculations across your laptop, workstations and clusters, with per-job workspaces and result readback.
vibe-view
A desktop app for structures, orbitals, densities and spectra — with a live update feed on macOS, Linux and Windows.
vibe-basis
A basis-set optimization driver — tune Gaussian basis sets against the systems and methods you actually run.
v0.15 — Neese's Cheetah
The public site tracks the release branch — a fast-forward-only snapshot of main. Release codenames pair a scientist with an animal.
- correlationDLPNO-CCSD(T) — local density fitting, sparse pair lists, open-shell pilots.
- excitedTD-DFT engine — Casida + TDA with NTOs and UV/Vis reconstruction.
- multirefCASSCF & IC-CASPT2 gradients — analytic, FD-pinned, driving optimization.
- periodicPeriodic-DFT accuracy fix — cross-cell XC within ~1 mHa of CRYSTAL23 on dense ionic crystals.
Built by one person. Kept alive by ♥ sponsors.
vibe-qc is developed in evenings and weekends, on a single laptop, with no institutional backing. Sponsorship funds the compute, the self-hosted server behind vibe-qc.com, and — most urgently — bigger hardware to lift the caps on every regression test and benchmark.
// maintained by Michael F. Peintinger · mpei@vibe-qc.com