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vibe-qc documentation
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Getting started

  • Installation
  • Quickstart — your first 30 minutes
  • Using Claude to drive vibe-qc
  • Running vibe-qc
  • Good practices
  • Troubleshooting
  • Updating vibe-qc
  • Tour of the vibe-qc API
  • Tutorial
    • Molecular Hartree-Fock
    • Molecular DFT (RKS)
    • Open-shell systems (UHF, UKS, UMP2)
    • Initial guesses — hands-on walkthrough
    • Non-mean-field solvers — Selected-CI, DMRG, v2RDM, and transcorrelated methods
    • Semiempirical DFTB — fast preoptimization
    • Post-SCF properties: charges, bonds, dipole
    • Geometry optimization
    • Vibrational frequencies
    • Thermodynamics at temperature
    • Orbital and density visualization
    • Basis-set convergence
    • Dispersion corrections (D3-BJ)
    • DFT functional comparison
    • Range-separated hybrids: ωB97X and the HOMO ≈ −IP property
    • Nudged Elastic Band: reaction paths & transition states
    • Natural orbitals and the idempotency diagnostic
    • RIJCOSX SCF + analytic gradient on glycine
    • Pt cluster with LANL2DZ — heavy-element ECP
    • Double hybrid: B2PLYP step by step
    • Verifying an RI-MP2 auxiliary basis
    • Solvation in water (CPCM)
    • Stiff molecular SCF: rescuing oscillation with EDIIS+DIIS
    • Periodic HF on a 1D H chain
    • Periodic KS-DFT
    • Madelung constants via Ewald summation
    • Band structure and density of states
    • Why solid-state calculations use pob-TZVP
    • Peierls dimerisation of a 1D H-chain
    • Projected density of states (PDOS)
    • Periodic orbital cubes and XSF files
    • Tight-cell DFT with the periodic Becke partition
    • Periodic SCF convergence: damping, DIIS, and level shifts
    • Symmetry-aware storage of lattice integrals (SYM3a)
    • Solid-state walkthrough: LiH rocksalt with pob-TZVP
    • Tutorial 30: H-chain BvK equivalence — vibe-qc’s CCM ancestor
    • 33. MgO from Materials Project — vqfetch end-to-end
    • 34. LiH at multi-k — KRHF targeting Peintinger 2013 SI Table 2
    • 35. Open-shell Mg⁺• in a periodic box — UHF GDF + Makov-Payne
    • Fermi-Dirac smearing for metals and small-gap solids
    • 43 — XSF and BXSF: periodic volumetric visualisation
    • Running in parallel
    • Tutorial 26: Cross-validating against ORCA, Psi4, PySCF
    • Tutorial 27: Viewing geometries, orbitals, and vibrations with MolTUI
    • Tutorial 29: Reproducing a reference output
    • Auto-citations: from .out to manuscript bibliography
    • Submitting a job to a remote machine with vq
    • Tutorial 45: vibe-view end-to-end walkthrough

User guide

  • User guide
    • Molecules
    • Basis sets
    • Functionals
    • MP2 and double hybrids
    • Non-mean-field solvers (vibeqc.solvers)
    • Composite “3c” methods
    • The data_library/ parameter-storage standard
    • Effective core potentials (ECPs)
    • Implicit solvation (CPCM / COSMO)
    • Density fitting (RIJ / RIJK / RIJCOSX)
    • Periodic systems
    • Crystal lattices
    • Slabs and adsorbates
    • k-point meshes
    • Multi-k periodic SCF
    • Ewald summation in periodic systems
    • CRYSTAL-style BIPOLE periodic HF and DFT
    • Plane-wave Hartree-J via GPW (experimental)
    • Periodic-SCF methods: BIPOLE, GDF, GPW / GAPW
    • DFT+U (Hubbard correction)
    • Relaxed coordinate scans
    • SCF convergence
    • Smearing (fractional occupations for periodic SCF)
    • SCF Fock-build modes
    • Initial guesses
    • Linear dependence and screening in periodic SCF
    • Memory budget
    • Settings introspection
    • BLAS + LAPACK backend
    • ASE integration
    • Nudged Elastic Band (NEB)
    • External QC codes (ORCA / Psi4 / others)
    • External structures (vqfetch)
    • Moving from PySCF
    • Moving from CRYSTAL
    • Moving from ORCA
    • Moving from Gaussian
    • Experimental reference data (vqfetch reference)
    • Input scripts and output files
    • Automatic citations
    • Post-SCF properties
    • Band structure and density of states
    • Volumetric data: cube, XSF, and BXSF files
    • vibe-view: interactive viewer
    • The vq calculation queue
    • Running vibe-qc from Jupyter Lab

Reference

  • Python API reference
    • vibeqc.Atom
    • vibeqc.Molecule
    • vibeqc.BasisSet
    • vibeqc.ShellInfo
    • vibeqc.from_xyz
    • vibeqc.RHFOptions
    • vibeqc.RHFResult
    • vibeqc.run_rhf
    • vibeqc.UHFOptions
    • vibeqc.UHFResult
    • vibeqc.run_uhf
    • vibeqc.RKSOptions
    • vibeqc.RKSResult
    • vibeqc.run_rks
    • vibeqc.UKSOptions
    • vibeqc.UKSResult
    • vibeqc.run_uks
    • vibeqc.MP2Result
    • vibeqc.run_mp2
    • vibeqc.UMP2Result
    • vibeqc.run_ump2
    • vibeqc.run_job
    • vibeqc.write_molden
    • vibeqc.write_orca_hess
    • vibeqc.write_xyz_trajectory
    • vibeqc.write_opt_trajectory
    • vibeqc.normal_mode_trajectory
    • vibeqc.format_scf_trace
    • vibeqc.log_scf_trace
    • vibeqc.compute_overlap
    • vibeqc.compute_kinetic
    • vibeqc.compute_nuclear
    • vibeqc.compute_eri
    • vibeqc.compute_gradient
    • vibeqc.compute_gradient_uhf
    • vibeqc.compute_gradient_rks
    • vibeqc.compute_gradient_uks
    • vibeqc.Functional
    • vibeqc.XCKind
    • vibeqc.build_grid
    • vibeqc.Grid
    • vibeqc.GridOptions
    • vibeqc.evaluate_ao
    • vibeqc.evaluate_ao_with_gradient
    • vibeqc.PeriodicSystem
    • vibeqc.LatticeCell
    • vibeqc.LatticeMatrixSet
    • vibeqc.LatticeSumOptions
    • vibeqc.CoulombMethod
    • vibeqc.BlochKMesh
    • vibeqc.BandDiag
    • vibeqc.direct_lattice_cells
    • vibeqc.bloch_sum
    • vibeqc.monkhorst_pack
    • vibeqc.diagonalize_bloch
    • vibeqc.compute_overlap_lattice
    • vibeqc.compute_kinetic_lattice
    • vibeqc.compute_nuclear_lattice
    • vibeqc.nuclear_repulsion_per_cell
    • vibeqc.compute_nuclear_erfc_lattice
    • vibeqc.EwaldOptions
    • vibeqc.ewald_point_charge_energy
    • vibeqc.ewald_nuclear_repulsion
    • vibeqc.build_jk_gamma_molecular_limit
    • vibeqc.build_fock_2e_real_space
    • vibeqc.build_xc_periodic
    • vibeqc.real_space_density_from_kpoints
    • vibeqc.PeriodicRHFOptions
    • vibeqc.PeriodicRHFResult
    • vibeqc.run_rhf_periodic_gamma
    • vibeqc.PeriodicSCFOptions
    • vibeqc.run_rhf_periodic
    • vibeqc.PeriodicKSOptions
    • vibeqc.PeriodicKSResult
    • vibeqc.run_rks_periodic
    • vibeqc.Crystal
    • vibeqc.SpaceGroup
    • vibeqc.SymmetryOp
    • vibeqc.IrreducibleKMesh
    • vibeqc.analyze_symmetry
    • vibeqc.attach_symmetry
    • vibeqc.to_primitive
    • vibeqc.irreducible_kpoints
    • vibeqc.read_poscar
    • vibeqc.write_poscar
    • vibeqc.spglib_version
    • vibeqc.mulliken_charges
    • vibeqc.loewdin_charges
    • vibeqc.mayer_bond_orders
    • vibeqc.dipole_moment
    • vibeqc.DipoleMoment
    • vibeqc.center_of_mass
    • vibeqc.compute_dipole
    • vibeqc.DipoleIntegrals
    • vibeqc.ProgressLogger
    • vibeqc.resolve_progress
    • vibeqc.system_info
    • vibeqc.write_system_manifest
    • vibeqc.PerfTracker
    • vibeqc.PerfScope
    • vibeqc.perf_log
    • vibeqc.active_tracker
    • vibeqc.format_perf_report
    • vibeqc.StructuredLog
    • vibeqc.structured_log
    • vibeqc.active_structured_log
    • vibeqc.run_fingerprint
    • vibeqc.dump_on_failure
    • vibeqc.load_dump
    • vibeqc.classify_failure
    • vibeqc.crash_dump_context
    • vibeqc.MemoryEstimate
    • vibeqc.InsufficientMemoryError
    • vibeqc.estimate_memory
    • vibeqc.check_memory
    • vibeqc.available_memory_bytes
    • vibeqc.format_memory_report
    • vibeqc.VIBEQC_VERSION
    • vibeqc.banner
    • vibeqc.print_banner
    • vibeqc.library_versions
    • vibeqc.libint_version
    • vibeqc.libxc_version
    • vibeqc.spglib_version
    • vibeqc.basis_crystal
    • vibeqc.KPath
    • vibeqc.BandStructure
    • vibeqc.DensityOfStates
    • vibeqc.kpath_from_segments
    • vibeqc.band_structure
    • vibeqc.band_structure_hcore
    • vibeqc.density_of_states
    • vibeqc.density_of_states_hcore
    • vibeqc.plot.band_structure_figure
    • vibeqc.plot.dos_figure
    • vibeqc.plot.bands_dos_figure
    • vibeqc.CubeGrid
    • vibeqc.make_uniform_grid
    • vibeqc.write_cube_density
    • vibeqc.write_cube_mo
    • vibeqc.write_cube_mos
    • vibeqc.write_xsf_structure
    • vibeqc.write_xsf_volume
    • vibeqc.write_bxsf
    • vibeqc.SCFAccelerator
    • vibeqc.InitialGuess
    • vibeqc.ADIIS
    • vibeqc.EDIIS
    • vibeqc.SCFMode
    • vibeqc.NewtonOptions
    • vibeqc.SOSCFOptions
    • vibeqc.SmearingOptions
    • vibeqc.Hamiltonian
    • vibeqc.solve_selected_ci
    • vibeqc.SelectedCIOptions
    • vibeqc.solve_dmrg
    • vibeqc.DMRGOptions
    • vibeqc.solve_v2rdm
    • vibeqc.V2RDMOptions
    • vibeqc.build_transcorrelated_hamiltonian
    • vibeqc.TranscorrelatedOptions
    • vibeqc.SolverResult
    • vibeqc.solvers.generate_determinants
    • vibeqc.solvers.build_hamiltonian_matrix_unrestricted
    • vibeqc.solvers.diagonal_matrix_element_unrestricted
    • vibeqc.get_hf_orbital_provider
    • vibeqc.build_hamiltonian_mo
    • vibeqc.solvers.transform_hamiltonian
    • vibeqc.run_double_hybrid
    • vibeqc.DoubleHybridResult
    • vibeqc.run_wb97x_d
    • vibeqc.WB97XDResult
    • vibeqc.ShortRangeCorrection
    • vibeqc.MP2Options
    • vibeqc.compute_d3bj
    • vibeqc.compute_d4
    • vibeqc.compute_chg_dispersion
    • vibeqc.compute_gcp
    • vibeqc.eeq_charges
    • vibeqc.DispersionResult
    • vibeqc.D4Result
    • vibeqc.GCPResult
    • vibeqc.EEQResult
    • vibeqc.EEQOptions
    • vibeqc.PeriodicDispersionResult
    • vibeqc.CPCMResult
    • vibeqc.SolventResult
    • vibeqc.optimize_molecule
    • vibeqc.MolecularOptimizeResult
    • vibeqc.OptimizeResult
    • vibeqc.HessianFDOptions
    • vibeqc.HessianResult
    • vibeqc.CPHFOptions
    • vibeqc.NEBResult
    • vibeqc.ScanResult
    • vibeqc.run_rhf_periodic_gamma_gdf
    • vibeqc.run_krhf_periodic_gdf
    • vibeqc.run_krks_periodic_gdf
    • vibeqc.run_rhf_periodic_gamma_ewald3d
    • vibeqc.run_rks_periodic_gamma_ewald3d
    • vibeqc.run_uhf_periodic_gamma_ewald3d
    • vibeqc.run_uks_periodic_gamma_ewald3d
    • vibeqc.run_rhf_periodic_multi_k_ewald3d
    • vibeqc.run_rks_periodic_multi_k_ewald3d
    • vibeqc.run_uhf_periodic_multi_k_ewald3d
    • vibeqc.run_pbc_bipole_rhf
    • vibeqc.run_pbc_bipole_uhf
    • vibeqc.run_pbc_bipole_rks
    • vibeqc.run_pbc_bipole_uks
    • vibeqc.run_periodic_job
    • vibeqc.PeriodicRHFGDFResult
    • vibeqc.PeriodicRHFEwaldResult
    • vibeqc.PeriodicRHFMultiKEwaldResult
    • vibeqc.PeriodicRKSEwaldResult
    • vibeqc.PeriodicRKSMultiKEwaldResult
    • vibeqc.PeriodicUHFEwaldResult
    • vibeqc.PeriodicUHFMultiKEwaldResult
    • vibeqc.PeriodicUKSEwaldResult
    • vibeqc.PeriodicUKSMultiKEwaldResult
    • vibeqc.PeriodicKRHFGDFResult
    • vibeqc.PeriodicKRKSGDFResult
    • vibeqc.PBCBipoleRHFResult
    • vibeqc.PBCBipoleUHFResult
    • vibeqc.PBCBipoleRKSResult
    • vibeqc.PBCBipoleUKSResult
    • vibeqc.PBCGDFResult
    • vibeqc.compute_gradient_periodic_rhf_gamma
    • vibeqc.compute_gradient_periodic_rks_gamma
    • vibeqc.compute_stress_tensor
    • vibeqc.hirshfeld_charges
    • vibeqc.HirshfeldResult
    • vibeqc.ECPCenter
    • vibeqc.auto_ecp_centers
    • vibeqc.compute_ecp_matrix
    • vibeqc.output.formats.qvf.write_qvf
    • vibeqc.output.formats.qvf.validate_qvf
    • vibeqc.output.formats.qvf.qvf_density_data
    • vibeqc.output.formats.qvf.qvf_mo_data
    • vibeqc.ThermoResult
  • Example outputs
  • Feature matrix
  • Roadmap

Project

  • Changelog
  • Release process
  • Contributing to vibe-qc
  • Support vibe-qc
  • Sponsors
  • How to cite vibe-qc
  • License + bundled-data inventory
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vibeqc.solve_v2rdm¶

vibeqc.solve_v2rdm(hamiltonian, options=None)[source]¶

One-shot v2RDM solve.

Parameters:
  • hamiltonian (Hamiltonian)

  • options (V2RDMOptions | None)

Return type:

SolverResult

Next
vibeqc.V2RDMOptions
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vibeqc.DMRGOptions
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  • vibeqc.solve_v2rdm
    • solve_v2rdm()