Keyword index¶

Common SCF and job option keywords in vibe-qc, with their default values. These options live on the per-method option objects (RHFOptions, RKSOptions, UHFOptions, UKSOptions, and their periodic counterparts PeriodicRHFOptions and PeriodicKSOptions), which you pass to a run via rhf_options=, rks_options=, ks_options=, and so on. The defaults below are the values a freshly constructed options object carries; this page is the flat lookup, and each section links the topic page with the physics.

Convergence and tolerances¶

Keyword	Default	Meaning
`max_iter`	`100`	Maximum SCF iterations.
`conv_tol_energy`	`1e-8`	SCF energy-change convergence threshold (Hartree).
`conv_tol_grad`	`1e-6`	Orbital-gradient (DIIS-error) convergence threshold.

See scf_convergence.

SCF acceleration and damping¶

Keyword	Default	Meaning
`scf_accelerator`	`EDIIS_DIIS` (molecular + periodic)	Extrapolation scheme; one of `DIIS`, `EDIIS`, `EDIIS_DIIS`, `ADIIS`, `ADIIS_DIIS`, `KDIIS`, `R_CDIIS`, `AD_CDIIS`.
`use_diis`	`True`	Enable DIIS extrapolation.
`diis_start_iter`	`2`	Iteration at which DIIS begins.
`diis_subspace_size`	`8`	Number of stored vectors. EDIIS, ADIIS, and their hybrids accept 2-12; plain DIIS-family accelerators may use deeper histories.
`ediis_diis_switch_threshold`	`0.1`	Intensive (RMS matrix-element) DIIS error at which EDIIS hands over to plain DIIS.
`ediis_diis_switch_threshold_open_shell`	`1e-3` (UHF only)	Same, used instead when n_α ≠ n_β (#377).
`diis_restart_tau`	`1e-4`	R_CDIIS restart parameter τ ∈ (0,1) (Chupin et al. 2021); smaller ⇒ deeper history.
`diis_adaptive_delta`	`1e-4`	AD_CDIIS depth parameter δ > 0 (Chupin et al. 2021); smaller ⇒ deeper history.
`damping`	`0.5`	Finite static density/Fock damping fraction in `[0, 1)`.
`dynamic_damping`	`True` (molecular + periodic)	Adjust the damping factor automatically (ORCA/CRYSTAL-style; default v0.15.x).
`dynamic_damping_min` / `_max`	`0.0` / `0.95`	Bounds for dynamic damping.
`fock_mixing`	`0.0`	Finite CRYSTAL-style static Fock-mixing fraction in `[0, 1)` (FMIXING).
`level_shift`	`0.0`	Saunders-Hillier virtual-orbital level shift (Hartree). Molecular + periodic.
`level_shift_warmup_cycles`	`-1`	Auto-reducing shift warm-up: `-1` auto (shift a few startup cycles then release), `0` persistent, `N` explicit length. Molecular + periodic.
`level_shift_schedule`	`[]`	Explicit per-iteration shift curve (CRYSTAL `LEVSHIFT B IRESET`); supersedes `level_shift` + warm-up. Lower a `LevelShiftSchedule` via `.apply_to(opts)`. Molecular + periodic.

See scf_convergence.

Second-order and Newton methods¶

Each is off (0.0) by default and turns on when the DIIS error drops below the given threshold.

Keyword	Default	Meaning
`newton_threshold`	`0.0` (off)	Switch to full-Hessian Newton below this DIIS error.
`soscf_threshold`	`0.0` (off)	Opt-in: switch to the second-order SOSCF (L-BFGS quasi-Newton) finalizer below this error norm; `0.0` disables.
`trah_threshold`	`0.0` (off)	Switch to trust-region augmented-Hessian (TRAH).
`quadratic_fallback_iter`	`0` (off)	Iteration at which to trigger the quadratic fallback.

Iterative diagonalization (Davidson)¶

Keyword	Default	Meaning
`use_davidson`	`False`	Replace full diagonalization with blocked Davidson.
`davidson_min_dim`	`100`	Minimum AO basis size to activate Davidson.
`davidson`	`DavidsonOptions()`	Per-knob Davidson control.
`solver`	`"dense"`	Diagonalization keyword: `"dense"`, `"davidson"`, or `"lobpcg"`.

Initial guess¶

Keyword	Default	Meaning
`initial_guess`	`AUTO` (molecular and periodic)	Starting density; one of `AUTO`, `HCORE`, `SAD`, `SAP`, `PATOM`, `HUECKEL` (`HUCKEL` alias), `MINAO`, `READ`, or `FRAGMO` on supported molecular and periodic routes.
`read_path`	`''`	File (`.qvf` / `.molden`) to read orbitals from, for `initial_guess=READ`.

See initial_guess.

Fock-build strategy¶

Keyword	Default	Meaning
`scf_mode`	`AUTO`	`AUTO`, `CONVENTIONAL` (in-core), or `DIRECT` (on-the-fly, screened).
`scf_mode_auto_threshold`	`140`	Basis size above which `AUTO` selects `DIRECT`.
`density_fit`	`False`	Use RI / density fitting for the Coulomb (J) build.
`cosx`	`False`	Use COSX-K inside the density-fitting route. `run_job(cosx=True)` enables DF automatically; low-level option objects must also set `density_fit=True`.
`schwarz_threshold`	`1e-10`	Schwarz integral-screening threshold.
`schwarz_threshold_loose`	`1e-7`	Early-iteration Schwarz threshold; set no larger than `schwarz_threshold` to disable loose screening.
`schwarz_threshold_tighten_at`	`1e-3`	SCF gradient norm below which direct SCF switches to `schwarz_threshold`.
`incremental_fock`	`True`	Build the Fock matrix incrementally between iterations on the direct path.
`incremental_fock_reset_freq`	`8`	Full direct-Fock rebuild interval used to bound incremental drift.

See scf_modes and density_fitting.

Basis, auxiliary, and ECP¶

Keyword	Default	Meaning
`aux_basis`	`''`	Auxiliary fitting-basis label. `run_job` auto-selects one for DF/COSX when possible; low-level `run_rhf` / `run_rks` / `run_uhf` / `run_uks` require an explicit value.
`ecp_library`	`''`	Effective-core-potential library name.
`ecp_centers`	`[]`	Per-center ECP assignments.
`linear_dep_threshold`	`1e-7`	Overlap-eigenvalue cutoff for linear-dependence filtering.

See basis_sets, ecp, linear_dependence.

DFT (RKS / UKS)¶

Keyword	Default	Meaning
`functional`	`'LDA'`	XC functional: a libxc name, weighted-sum specification, or registered external full-grid provider such as `skala-1.1`.
`grid`	(medium grid)	XC quadrature grid; a `GridOptions` object (see below).
`grid_level`	`"orca-defgrid3"` (argument of `run_job`)	High-level grid preset, applied whenever the KS options’ grid is untouched (no options object, or one whose `grid` was never customised, #663); a customised grid wins. Exact SKALA aliases automatically select `"skala"` on an untouched grid.

See functionals and Microsoft SKALA-1.1.

XC grid (`GridOptions`)¶

Keyword	Default	Meaning
`partition`	`Becke`	Atomic partitioning scheme.
`angular`	`ProductGaussLegendre`	Angular quadrature; `ProductGaussLegendre` or `Lebedev`.
`n_radial`	`75`	Radial quadrature points.
`n_theta` / `n_phi`	`17` / `36`	Product-grid angular points.
`lebedev_order`	`29`	Lebedev order (used when `angular=Lebedev`): 5, 7, 11, 15, 17, 23, 27, 29, 31, 35, 41, 47, 53, and for convergence studies 59, 65, 77, 95 (1202 to 3074 points). See the grid tutorial.
`becke_k`	`3`	Becke partition smoothing order.
`vv10_grid_factor`	`3.0`	VV10-paired functionals (`vv10`, `wb97x-v`, `wb97m-v`) evaluate the nonlocal double integral on a separate grid with the radial and angular resolution divided by this factor (Vydrov and Van Voorhis 2010 practice). `1.0` (or `0`) evaluates VV10 on the full XC grid, the bitwise pre-v0.16 reference.
`atomic_grid_profile`	`Generic`	Coherent atom-specific grid contract. `"pyscf-level3"` or `"skala"` selects vibe-qc’s pinned SKALA parity profile and overrides the individual radial, angular, pruning, and partition controls.

Open-shell (UHF / UKS, and periodic)¶

Keyword	Default	Meaning
`atomic_spins`	`[]`	Per-atom broken-symmetry spin seed (the ATOMSPIN analogue).
`spinlock_mode`	`OFF`	Broken-symmetry hold mode for the spin pattern.
`spinlock_iterations`	`0`	Iterations to hold the spin pattern.
`spinlock_value`	`0`	The locked spin value.
`stability_check`	`True`	Molecular UHF/UKS: post-convergence internal stability analysis + corrective restart; implicit UKS checks skip when the complete response is unavailable (meta-GGA, range-separated, VV10, DFT+U, active hybrid RIJCOSX, or coupled solvent) (details).
`stability_tol`	`1e-4`	Instability threshold on the lowest orbital-rotation Hessian eigenvalue.
`stability_max_retries`	`3`	Rotate-and-reconverge escapes before reporting the instability unresolved.
`stability_davidson_max_iter`	`80` (UHF), `60` (UKS)	Matvec cap per stability eigensolve (one J + two K builds each).

Periodic (`PeriodicRHFOptions` / `PeriodicKSOptions`)¶

The periodic option objects share the convergence, acceleration, damping, level-shift, initial-guess, and iterative-diagonalization controls above. They do not carry the molecular scf_mode, density-fitting, COSX, or direct-SCF screening fields; periodic J/K algorithms are selected by route instead. The periodic scf_accelerator default is EDIIS_DIIS, the same as molecular. Periodic jobs additionally expose:

Keyword	Default	Meaning
`jk_method`	`AUTO` (argument of `run_periodic_job`)	Coulomb route: `GDF`, `BIPOLE`, `GPW`, `GAPW`, `RSGDF`, and others. See choosing a periodic method. The AICCM formulations are not `jk_method` values: select them with `method="aiccm"` and `variant=` (see AICCM); with `method="aiccm"`, `jk_method` stays `AUTO` or must equal the variant’s own route.
`variant`	(none; mandatory with `method="aiccm"`)	AICCM formulation: `"real-gamma"`, `"neutral-bloch"`, `"chi"`, and `"four-center"`. All four runner arms are wired and experimental; each keeps its documented, fail-closed capability envelope.
`scf_reference`	`None` (argument of `run_periodic_job`, `method="aiccm"` only)	`None` infers the SCF reference (`functional` decides HF versus KS; the multiplicity and electron parity decide restricted versus unrestricted); `"rhf"` / `"uhf"` request a Hartree-Fock reference explicitly on every variant (no `functional`; `"uhf"` mainly for a closed-shell singlet, `"rhf"` refused on an odd electron count); `"rohf"` / `"roks"` request the restricted open-shell references explicitly (no variant implements them yet; fails closed).
`aiccm_lattice_extension`	`None` (argument of `run_periodic_job`)	Born-von Karman torus `(N1, N2, N3)` for every AICCM variant; `kpoints` is the legacy Γ-centred alias for the torus mesh, never both. `aiccm_wigner_seitz_shells=s` is the odd-extension shorthand for `2s+1`.
`aiccm_cderi_storage`	`None` (argument of `run_periodic_job`, `variant="real-gamma"` only)	How the real-Gamma producer holds its fitted integrals: `"dense"` (what `None` runs; memory grows as the cube of the torus size), `"block"` (one block per transfer of the block-circulant torus) or `"block-star"` (only the fits of the k-pair star plan). One operator in every storage; recorded as `cderi_storage_executed`. Not combinable with `correlation=`. See AICCM.
`smearing_temperature`	`0.0`	Fermi-Dirac smearing temperature (Hartree); `0.0` is no smearing.
`use_periodic_becke`	`True` (KS)	Use the periodic Becke partition for the XC grid.
`becke_image_radius_bohr`	`10.0` (KS)	Minimum point-centered image radius for the periodic Becke partition; converge with the grid resolution.
`lattice_opts`	(`LatticeSumOptions`)	Real-space cutoffs for the lattice sums (`cutoff_bohr`, `nuclear_cutoff_bohr`, …).
`bipole_cutoff_bohr`	`15.0` (argument of `run_periodic_job`, BIPOLE route)	Direct-lattice cutoff of the electronic BIPOLE Fock sums; raise until the reported Bloch-overlap fold drift is < 1e-4 (a drift ≥ 1e-2 refuses SCF).
`use_exchange_ewald_split`	`None` (auto)	Corrected Ewald exchange split (`K = K_SR + K_LR + G=0` term). Auto-ON for 3D BIPOLE runs at Γ and Monkhorst-Pack multi-k; `False` restores the legacy Γ-locality gauge.
`exchange_exxdiv`	`"ewald"`	Exact-exchange G=0 convention: `"ewald"` (probe-charge Madelung, PySCF-equivalent, already near the k-converged limit) or `"none"`. The two differ by exactly `½·N_e·ξ_M(BvK supercell)`; see from_crystal § Comparing total energies.
`ewald_precision`	`1e-8`	Truncation target of the real/reciprocal Ewald lattice sums (BIPOLE route).
`rcut_strategy`	`"pyscf_auto"` (argument of the GDF drivers)	Sizes the one-electron domain (pair complete, measured to 1e-16 of the largest overlap) and the KS exchange-correlation image domain (`2 r_ao + span`) from the basis; `"flat"` keeps `cutoff_bohr` everywhere. The fitted J/K sums use `cutoff_bohr` either way. See the lattice-cutoff tutorial.
`fit_source`	`"auto"` (argument of `run_periodic_job` and the GDF drivers)	GDF fit: the default range-separated source, or `"classic"`.
`classic_support_policy`	`None` (physical pairs) (GDF drivers)	AO-pair support of the classic fit; `"historical_index_ball"` replays the pre-#466 operator. A positive `fit_screen_threshold` needs the historical ball.
`check_energy_sanity`	`True` (GDF drivers)	Raise `RuntimeError` on a converged total energy outside the physical range; `False` returns the raw value for diagnostics.
`symmetry_reduce_k`	`False` (argument of `run_periodic_job`)	Build exact exchange on the irreducible wedge and transport it over each star (preview; needs `symmetry="attach"`, a multi-k mesh and exact exchange). See the tutorial.
`conv_tol_grad`	`None` (argument of `run_periodic_job`)	Explicit SCF gradient tolerance, also on the BIPOLE routes; the executed value is printed in the `.out`.

See periodic_methods, smearing, multi_k_scf.

Correlation and integral-engine selection¶

Keyword	Default	Meaning
`dlpno_thresholds`	`None` (NormalPNO) (argument of `run_job` and `run_periodic_job`)	`"loose"`, `"normal"`, `"tight"` or a `DLPNOThresholds` record. See DLPNO.
`dlpno_ccsd_options`	`None`	`LocalCCSDOptions` (RHF) or `LocalUCCSDOptions` (UHF); on crystals a `LocalUCCSDOptions` also selects a UHF reference.
`frozen_core`	`None` (published count)	ORCA 6.1 count-only convention; `False` correlates all electrons; an integer is an explicit count (per cell on crystals).
`integral_engine`	`None` (argument of `run_job` and `run_periodic_job`)	`IntegralEngineOptions(backend="libint" \| "manta", budget=...)`; experimental. See integral engines.
`coulomb`	`None`	`CoulombBuildOptions(algorithm="exact" \| "ri" \| "bupo" \| "ri_bupo", auxiliary_basis=...)`.
`exchange`	`None`	`ExchangeBuildOptions(algorithm="exact" \| "ri")`.
`periodic_integrals`	`None` (argument of `run_periodic_job`)	`PeriodicIntegralOptions(reciprocal_energy_cutoff, pair_cutoff_bohr, nuclear_cutoff_bohr, alpha=0.7)`; required with a periodic MANTA job.
`periodic_xc`	`None`	`PeriodicXCOptions(xc_image_cutoff_bohr, radial_points=50, lebedev_order=29, ...)`; required for periodic MANTA RKS/UKS.
`periodic_fitting`	`None`	`PeriodicFittingOptions(omega, auxiliary_cutoff_bohr, ...)`; required when a periodic MANTA J or K is RI.
`symmetry_reduction`	`None` (argument of `run_job`, `run_rhf`, `run_uhf`)	Experimental molecular point-group reduction of the RHF/UHF J/K build: `MolecularSymmetryOptions`, `MolecularRISymmetryOptions` or a process-local `PreparedMolecularSymmetry`. Refuses geometry derivatives, response, correlation, solvation, dispersion and other engines. See the developer reference and symmetry status.

Enumerations¶

The values each option enum accepts (the default is marked):

InitialGuess: AUTO (molecular and periodic default), HCORE, SAD, SAP, PATOM, HUECKEL (HUCKEL alias), MINAO, READ, FRAGMO. Availability depends on the execution route.
SCFAccelerator: DIIS, EDIIS, EDIIS_DIIS (molecular and periodic default), ADIIS, ADIIS_DIIS, KDIIS, R_CDIIS, AD_CDIIS (adaptive-depth CDIIS, Chupin et al. 2021).
SCFMode: AUTO (default), CONVENTIONAL, DIRECT.
PeriodicJKMethod: AUTO (default), GDF, BIPOLE, GPW, GAPW, SLAB_EWALD_2D, RIJCOSX, DIRECT, FFT_POISSON (retired), RSGDF and CFMM (reserved), and the four AICCM members AICCM2026DEV_A ("aiccm2026dev-a"), AICCM2026DEV_A_REAL_GAMMA (value "real-gamma"), NEUTRAL_BLOCH ("neutral-bloch") and AICCM2026DEV_B ("aiccm2026dev-b"), which are reached through run_periodic_job(method="aiccm", variant=...), not through jk_method.
CoulombMethod: EWALD_3D, DIRECT_TRUNCATED, NEUTRALIZED_1D, SLAB_EWALD_2D.
SpinlockMode: OFF (default), and the broken-symmetry hold modes.