pyscf-cli

Run real quantum chemistry from a single XYZ file and one command line.

pyscf-cli is an educational front-end to PySCF. Students run Hartree–Fock, DFT, MP2, and CCSD(T) calculations — plus geometry optimization, vibrational analysis, thermochemistry, molecular DOS plots, orbital visualization, and Δ-SCF excited states — without writing any Python. When they are ready to look under the hood, --dry-run prints the equivalent PySCF script for any calculation.

Note: pyscf-cli is an independent educational project developed at the Mochizuki group, Tokyo University of Science. It is not an official tool of the PySCF developers. Please cite PySCF itself in any academic work (see Citation).

日本語のREADMEは README_ja.md をご覧ください。

Installation

pip install pyscf-cli        # (after the PyPI release)
# development version:
pip install git+https://github.com/ahntaeyoung1212/pyscf-cli.git

Requires Python ≥ 3.9 on Linux or macOS. PySCF does not support Windows natively — Windows users should use WSL or simply run everything on Google Colab (%pip install pyscf-cli works there).

Five-minute quickstart

pyscf-cli examples h2o          # copy a bundled sample molecule to ./h2o.xyz
pyscf-cli energy h2o.xyz        # RHF/STO-3G single point

==============================================
 PySCF Calculation (pyscf-cli energy)
==============================================
XYZ file      : h2o.xyz
Basis         : sto-3g
...
Method        : RHF
Total Energy  : -2039.847777 eV
<S^2>         : 0.000000
Multiplicity  : 1.0

MO energies (Hartree / eV):
  MO  1: -20.242078  -550.8151
  ...

Not sure what to try? pyscf-cli examples lists the bundled molecules, pyscf-cli info explains every basis set, functional, and level of theory, and every subcommand has --help.

What can it do?

A tour:

pyscf-cli energy o2.xyz --spin 2 --method uhf              # triplet O2 (check <S^2> = 2!)
pyscf-cli energy h2o.xyz --theory dft --xc b3lyp --basis 6-31g**
pyscf-cli energy h2.xyz --pes --rmin 0.4 --rmax 3.0        # bond dissociation curve
pyscf-cli relax h2o.xyz --basis 6-31g
pyscf-cli vib h2o.xyz --basis 6-31g
pyscf-cli thermo h2o.xyz --basis 6-31g --temp 298.15
pyscf-cli dos benzene.xyz --element-pdos --align homo
pyscf-cli dos h2o.xyz --coop --cohp                        # bonding/antibonding analysis
pyscf-cli orbitals h2o.xyz --homo --lumo                   # cube files for VESTA
pyscf-cli vibmovie h2o.xyz --basis 6-31g                   # GIF per normal mode
pyscf-cli convert SDF_aspirin.sdf                          # PubChem SDF -> XYZ

Designed for teaching

• Helpful errors. Typos suggest fixes (Unknown basis '6-31g*8'. Did you mean '6-31g*'?); impossible charge/spin combinations explain what --spin means; saddle-point geometries trigger "this is not a minimum" warnings instead of silent nonsense.
• --dry-run is the bridge to real PySCF. It prints a runnable Python script equivalent to the CLI call — students go CLI → read the script → edit the script → graduate from the CLI.
• --json for auto-grading. Every calculation can emit machine-readable results (--json result.json, or --json - for pure JSON on stdout). Exit codes are meaningful: 0 = success, 2 = input error, 3 = SCF did not converge.
• Electron-configuration control. --spin sets the number of unpaired electrons; --occ-alpha 1,3 occupies arbitrary MOs per spin channel and holds that configuration during the SCF (maximum overlap method); the printed ⟨S²⟩ verifies what you actually converged to.
• Energy decompositions. --decompose-total-energy splits E into T + V_ne + U + J + V_nn (the sum is verified to equal E_SCF); --fixed-occ-decomp analyzes a frozen-orbital promotion and prints the exchange integral K with the resulting singlet/triplet estimates.

See docs/TEACHING_ja.md for ready-to-use classroom exercises (in Japanese).

Citation

If you use pyscf-cli in teaching or research, please cite PySCF, which does all the actual quantum chemistry:

Q. Sun et al., "Recent developments in the PySCF program package", J. Chem. Phys. 153, 024109 (2020). DOI: 10.1063/5.0006074

A citable DOI for pyscf-cli itself (Zenodo) will be provided with the first stable release.

License

MIT © 2026 Yasuhide Mochizuki, Tokyo University of Science. PySCF itself is licensed under Apache-2.0.