Research software for chemical physics
Build molecular models, follow quantum dynamics, and explore spectra with an open Python framework for chemical physics.
pip install pyqedfrom pyqed.qchem import Molecule
mol = Molecule(
atom="H 0 0 0; H 0 0 0.74",
unit="angstrom",
basis="sto-3g",
)
mol.build(eri="auto")
mf = mol.RHF().run()
print(f"RHF energy: {mf.e_tot:.8f} Ha")ExpectedRHF energy: -1.11675931 Ha
Choose a starting point
Choose a field and start with a small, runnable example.
Build H₂, run native RHF, and print a converged total energy.
Start with molecular construction and native integrals, then continue into MP2, CI, CASCI, and CASSCF research workflows.
≈5 min
Propagate a two-state avoided crossing with LDRFG.
Learn the locally diabatic representation on a small model before moving to molecular state surfaces, linked overlaps, and sparse grids.
Starter model
Follow dissipation and environmental memory in a spin–boson HEOM model.
Use Lindblad, Redfield, and hierarchy methods to evolve reduced density matrices and study relaxation and decoherence.
Starter model
Explore two-photon absorption and multidimensional optical signals.
Build nonlinear response from molecular energies and transition dipoles using sum-of-states and correlation-function approaches.
Response functions
Construct a fermionic MPO with automatic Jordan–Wigner strings.
Continue from operator construction to MPS, DMRG, TDVP, symmetry-aware algorithms, and optional active-space workflows.
Starter MPO
Research APIs and method coverage are evolving.Review method and benchmark scope →
Selected research
Explore the calculations, source code, and methods behind these research figures.
Electronic-state topology
Energy-gap topology, overlap links, and adiabatic potential-energy surfaces along coupled nuclear coordinates.
Nonadiabatic dynamics
Nuclear probability moves across three coupled electronic states over a 100-femtosecond trajectory.
Spectroscopy
A QDE/LDRFG spectrum shown alongside a shifted LDR reference and experimental line shape.
About the project
Maintained by Bing Gu · MIT license
PyQED: A Python Framework for Ab Initio Geometric Quantum Dynamics
Yujuan Xie, Xiaotong Zhu, Bing Gu · Chinese Journal of Chemical Physics (2026)
1.13 × 10⁻¹⁰ Ha · A scoped STO-3G comparison against PySCF 2.12.1 passed its 10⁻⁹-hartree tolerance. Inputs, raw output, hashes, and limitations are recorded.
Inspect the validation record ↗Python 3.10–3.13 · Platform wheels and a source archive are published on PyPI. Optional scientific backends are documented separately from the native core path.
Review installation options ↗v0.3.0 · Release artifacts are connected to tagged source, checksums, workflow records, and PyPI provenance attestations.
Read the 0.3.0 release ↗