Keyword index¶

Every SCF and job option keyword in vibe-qc, with its default value. 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), `DIIS` (periodic)	Extrapolation scheme; one of `DIIS`, `EDIIS`, `EDIIS_DIIS`, `ADIIS`, `KDIIS`.
`use_diis`	`True`	Enable DIIS extrapolation.
`diis_start_iter`	`2`	Iteration at which DIIS begins.
`diis_subspace_size`	`8`	Number of stored DIIS vectors.
`ediis_diis_switch_threshold`	`0.1`	DIIS-error at which EDIIS hands over to plain DIIS.
`damping`	`0.5`	Static density/Fock damping fraction.
`dynamic_damping`	`False`	Adjust the damping factor automatically.
`dynamic_damping_min` / `_max`	`0.0` / `0.95`	Bounds for dynamic damping.
`fock_mixing`	`0.0`	CRYSTAL-style static Fock mixing (FMIXING).
`level_shift`	`0.0`	Virtual-orbital level shift (Hartree).

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)	Switch to second-order SCF (SOSCF).
`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.

Initial guess¶

Keyword	Default	Meaning
`initial_guess`	`AUTO`	Starting density; one of `AUTO`, `HCORE`, `SAD`, `SAP`, `PATOM`, `HUECKEL`, `MINAO`, `READ`.
`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`	`200`	Basis size above which `AUTO` selects `DIRECT`.
`density_fit`	`False`	Use RI / density fitting for the Coulomb (J) build.
`cosx`	`False`	Use chain-of-spheres (RIJCOSX) for the exchange (K) build.
`schwarz_threshold`	`1e-10`	Schwarz integral-screening threshold.
`incremental_fock`	`False`	Build the Fock matrix incrementally between iterations.

See scf_modes and density_fitting.

Basis, auxiliary, and ECP¶

Keyword	Default	Meaning
`aux_basis`	`''`	Auxiliary (fitting) basis label; empty selects automatically.
`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 or a weighted-sum specification.
`grid`	(medium grid)	XC quadrature grid; a `GridOptions` object (see below).

See functionals.

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`).
`becke_k`	`3`	Becke partition smoothing order.

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.

Periodic (`PeriodicRHFOptions` / `PeriodicKSOptions`)¶

The periodic option objects share all the SCF keywords above (note the periodic scf_accelerator default is DIIS), and add:

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.
`smearing_temperature`	`0.0`	Fermi-Dirac smearing temperature (Hartree); `0.0` is no smearing.
`level_shift_warmup_cycles`	`-1`	Cycles over which to apply a warm-up level shift (`-1` = off).
`use_periodic_becke`	`True` (KS)	Use the periodic Becke partition for the XC grid.
`becke_image_radius_bohr`	`10.0` (KS)	Image radius for the periodic Becke partition.
`lattice_opts`	(`LatticeSumOptions`)	Real-space cutoffs for the lattice sums (`cutoff_bohr`, `nuclear_cutoff_bohr`, …).

See periodic_methods, smearing, multi_k_scf.

Enumerations¶

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

InitialGuess: AUTO (default), HCORE, SAD, SAP, PATOM, HUECKEL, MINAO, READ.
SCFAccelerator: DIIS, EDIIS, EDIIS_DIIS (molecular default), ADIIS, KDIIS.
SCFMode: AUTO (default), CONVENTIONAL, DIRECT.
PeriodicJKMethod: AUTO (default), GDF, AICCM2026DEV_B, BIPOLE, GPW, GAPW, RSGDF, RIJCOSX, FFT_POISSON, CFMM, DIRECT.
CoulombMethod: EWALD_3D, DIRECT_TRUNCATED, NEUTRALIZED_1D, SLAB_EWALD_2D.
SpinlockMode: OFF (default), and the broken-symmetry hold modes.