Your first calculation, in a few lines.
Install from PyPI, then run a Hartree–Fock calculation on water — no external quantum-chemistry program required. vibe-qc ships its own C++ engine.
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1 Install
$ pip install vibe-qcPrebuilt wheels for Linux and macOS. For a source build or the development branch, see the installation guide.
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2 Run RHF on water
import vibeqc as vq import numpy as np mol = vq.Molecule([ vq.Atom(8, [ 0.0, 0.00, 0.00]), vq.Atom(1, [ 0.0, 1.43, -0.98]), vq.Atom(1, [ 0.0, -1.43, -0.98]), ]) basis = vq.BasisSet(mol, "6-31g*") result = vq.run_rhf(mol, basis) eps = np.asarray(result.mo_energies) homo = mol.n_electrons() // 2 - 1 print(f"E(SCF) = {result.energy:.6f} Ha") print(f"ε(HOMO) = {eps[homo]*27.211386:.2f} eV") print(f"gap = {(eps[homo+1] - eps[homo])*27.211386:.2f} eV") -
3 Read the result
You get the SCF energy in hartree and the HOMO energy plus HOMO–LUMO gap in eV. Swap
run_rhfforrun_rks,run_mp2, or a periodic driver to go further — same front-end, same objects.