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# SCF

Performs self consistent field (Hartree-Fock and Density Functional Theory) computations. These are the starting points for most computations, so this code is called in most cases.

## General Wavefunction Info

### BASIS

> Primary basis set

> - Type: string
> - Possible Values: basis string
> - Default: No Default

### CHOLESKY_TOLERANCE

> Tolerance for Cholesky decomposition of the ERI tensor

> - Type: conv double
> - Default: 1e-4

### DF_BASIS_SCF

> Auxiliary basis set for SCF density fitting computations. Defaults to a JKFIT basis.

> - Type: string
> - Possible Values: basis string
> - Default: No Default

### DF_SCF_GUESS

> Use DF integrals tech to converge the SCF before switching to a conventional tech

> - Type: boolean
> - Default: true

### GUESS

> The type of guess orbitals. Defaults to CORE except for geometry optimizations, in which case READ becomes the default after the first geometry step.

> - Type: string
> - Possible Values: CORE, GWH, SAD, READ
> - Default: CORE

### INTS_TOLERANCE

> Minimum absolute value below which TEI are neglected.

> - Type: conv double
> - Default: 0.0

### MOLDEN_WRITE

> Do write a MOLDEN output file? If so, the filename will end in .molden, and the prefix is determined by WRITER_FILE_LABEL (if set), or else by the name of the output file plus the name of the current molecule.

> - Type: boolean
> - Default: false

### PRINT_BASIS

> Flag to print the basis set.

> - Type: boolean
> - Default: false

### PRINT_MOS

> Flag to print the molecular orbitals.

> - Type: boolean
> - Default: false

### REFERENCE

> Reference wavefunction type

> - Type: string
> - Possible Values: RHF, ROHF, UHF, CUHF, RKS, UKS
> - Default: RHF

### SAVE_JK

> Keep JK object for later use?

> - Type: boolean
> - Default: false

### SCF_MEM_SAFETY_FACTOR

> Memory safety factor for allocating JK

> - Type: double
> - Default: 0.75

### SCF_TYPE

> What algorithm to use for the SCF computation. See Table SCF Convergence & Algorithm for default algorithm for different calculation types.

> - Type: string
> - Possible Values: DIRECT, DF, PK, OUT_OF_CORE, FAST_DF, CD
> - Default: PK

### S_ORTHOGONALIZATION

> SO orthogonalization: symmetric or canonical?

> - Type: string
> - Possible Values: SYMMETRIC, CANONICAL
> - Default: SYMMETRIC

### S_TOLERANCE

> Minimum S matrix eigenvalue to be used before compensating for linear dependencies.

> - Type: conv double
> - Default: 1e-7

## Convergence Control/Stabilization

### BASIS_GUESS

> Accelerate convergence by performing a preliminary scf with this small basis set followed by projection into the full target basis. A value of `TRUE` turns on projection using the 3-21G small basis set.

> - Type: string
> - Default: FALSE

### DAMPING_CONVERGENCE

> The density convergence threshold after which damping is no longer performed, if it is enabled. It is recommended to leave damping on until convergence, which is the default.

> - Type: conv double
> - Default: 1.0e-18

### DAMPING_PERCENTAGE

> The amount (percentage) of damping to apply to the early density updates. 0 will result in a full update, 100 will completely stall the update. A value around 20 (which corresponds to 20% of the previous iteration’s density being mixed into the current density) could help to solve problems with oscillatory convergence.

> - Type: double
> - Default: 100.0

### DF_BASIS_GUESS

> When BASIS_GUESS is active, run the preliminary scf in density-fitted mode with this as fitting basis for the small basis set. A value of `TRUE` turns on density fitting with the cc-pVDZ-RI basis set (when available for all elements).

> - Type: string
> - Possible Values: basis string
> - Default: FALSE

### DIIS

> Do use DIIS extrapolation to accelerate convergence?

> - Type: boolean
> - Default: true

### DIIS_MAX_VECS

> Maximum number of error vectors stored for DIIS extrapolation

> - Type: integer
> - Default: 10

### DIIS_MIN_VECS

> Minimum number of error vectors stored for DIIS extrapolation

> - Type: integer
> - Default: 2

### DIIS_START

> The minimum iteration to start storing DIIS vectors

> - Type: integer
> - Default: 1

### D_CONVERGENCE

> Convergence criterion for SCF density, which is defined as the RMS value of the orbital gradient. See Table SCF Convergence & Algorithm for default convergence criteria for different calculation types.

> - Type: conv double
> - Default: 1e-6

### E_CONVERGENCE

> Convergence criterion for SCF energy. See Table SCF Convergence & Algorithm for default convergence criteria for different calculation types.

> - Type: conv double
> - Default: 1e-6

### FAIL_ON_MAXITER

> Fail if we reach maxiter without converging?

> - Type: boolean
> - Default: true

### MAXITER

> Maximum number of iterations

> - Type: integer
> - Default: 100

### MOM_OCC

> The absolute indices of orbitals to excite from in MOM (+/- for alpha/beta)

> - Type: array
> - Default: No Default

### MOM_START

> The iteration to start MOM on (or 0 for no MOM)

> - Type: integer
> - Default: 0

### MOM_VIR

> The absolute indices of orbitals to excite to in MOM (+/- for alpha/beta)

> - Type: array
> - Default: No Default

### STABILITY_ANALYSIS

> Whether to perform stability analysis after convergence. NONE prevents analysis being performed. CHECK will print out the analysis of the wavefunction stability at the end of the computation. FOLLOW will perform the analysis and, if a totally symmetric instability is found, will attemp to follow the eigenvector and re-run the computations to find a stable solution.

> - Type: string
> - Possible Values: NONE, CHECK, FOLLOW
> - Default: NONE

## Fractional Occupation UHF/UKS

### FRAC_DIIS

> Do use DIIS extrapolation to accelerate convergence in frac?

> - Type: boolean
> - Default: true

### FRAC_LOAD

> Do recompute guess from stored orbitals?

> - Type: boolean
> - Default: false

### FRAC_OCC

> The absolute indices of occupied orbitals to fractionally occupy (+/- for alpha/beta)

> - Type: array
> - Default: No Default

### FRAC_RENORMALIZE

> Do renormalize C matrices prior to writing to checkpoint?

> - Type: boolean
> - Default: true

### FRAC_START

> The iteration to start fractionally occupying orbitals (or 0 for no fractional occupation)

> - Type: integer
> - Default: 0

### FRAC_VAL

> The occupations of the orbital indices specified above ()

> - Type: array
> - Default: No Default

## Environmental Effects

### EXTERN

> An ExternalPotential (built by Python or NULL/None)

> - Type: python
> - Default: No Default

### ONEPOT_GRID_READ

> Read an external potential from the .dx file?

> - Type: boolean
> - Default: false

### PERTURB_H

> Do perturb the Hamiltonian?

> - Type: boolean
> - Default: false

### PERTURB_MAGNITUDE

> Size of the perturbation (applies only to dipole perturbations)

> - Type: double
> - Default: 0.0

### PERTURB_WITH

> The operator used to perturb the Hamiltonian, if requested

> - Type: string
> - Possible Values: DIPOLE_X, DIPOLE_Y, DIPOLE_Z, EMBPOT, SPHERE, DX
> - Default: DIPOLE_X

### PHI_POINTS

> Number of azimuthal grid points for sphereical potential integration

> - Type: integer
> - Default: 360

### RADIUS

> Radius (bohr) of a hard-sphere external potential

> - Type: double
> - Default: 10.0

### R_POINTS

> Number of radial grid points for sphereical potential integration

> - Type: integer
> - Default: 100

### THETA_POINTS

> Number of colatitude grid points for sphereical potential integration

> - Type: integer
> - Default: 360

### THICKNESS

> Thickness (bohr) of a hard-sphere external potential

> - Type: double
> - Default: 20.0

## DFSCF Algorithm

### DF_BUMP_R0

> Bump function min radius

> - Type: double
> - Default: 0.0

### DF_BUMP_R1

> Bump function max radius

> - Type: double
> - Default: 0.0

### DF_DOMAINS

> FastDF geometric fitting domain selection algorithm

> - Type: string
> - Possible Values: DIATOMIC, SPHERES
> - Default: DIATOMIC

### DF_INTS_NUM_THREADS

> Number of threads for integrals (may be turned down if memory is an issue). 0 is blank

> - Type: integer
> - Default: 0

### DF_METRIC

> FastDF Fitting Metric

> - Type: string
> - Possible Values: COULOMB, EWALD, OVERLAP
> - Default: COULOMB

### DF_THETA

> FastDF SR Ewald metric range separation parameter

> - Type: double
> - Default: 1.0

## SAD Guess Algorithm

### SAD_D_CONVERGENCE

> Convergence criterion for SCF density in SAD Guess.

> - Type: conv double
> - Default: 1e-5

### SAD_E_CONVERGENCE

> Convergence criterion for SCF energy in SAD Guess.

> - Type: conv double
> - Default: 1e-5

## DFT

### DFT_ALPHA

> The DFT Exact-exchange parameter

> - Type: double
> - Default: 0.0

### DFT_BASIS_TOLERANCE

> DFT basis cutoff.

> - Type: conv double
> - Default: 1.0e-12

### DFT_BS_RADIUS_ALPHA

> Factor for effective BS radius in radial grid.

> - Type: double
> - Default: 1.0

### DFT_CUSTOM_FUNCTIONAL

> A custom DFT functional object (built by Python or NULL/None)

> - Type: python
> - Default: No Default

### DFT_DISPERSION_PARAMETERS

> Parameters defining the dispersion correction. See Table -D Functionals for default values and Table Dispersion Corrections for the order in which parameters are to be specified in this array option.

> - Type: array
> - Default: No Default

### DFT_FUNCTIONAL

> The DFT combined functional name, e.g. B3LYP, or GEN to use a python reference to a custom functional specified by DFT_CUSTOM_FUNCTIONAL.

> - Type: string
> - Default: No Default

### DFT_NUCLEAR_SCHEME

> Nuclear Scheme.

> - Type: string
> - Possible Values: TREUTLER, BECKE, NAIVE, STRATMANN
> - Default: TREUTLER

### DFT_OMEGA

> The DFT Range-separation parameter

> - Type: double
> - Default: 0.0

### DFT_RADIAL_POINTS

> Number of radial points.

> - Type: integer
> - Default: 75

### DFT_RADIAL_SCHEME

> Radial Scheme.

> - Type: string
> - Possible Values: TREUTLER, BECKE, MULTIEXP, EM, MURA
> - Default: TREUTLER

### DFT_SPHERICAL_POINTS

> Number of spherical points (A Lebedev Points number).

> - Type: integer
> - Default: 302

### DFT_SPHERICAL_SCHEME

> Spherical Scheme.

> - Type: string
> - Possible Values: LEBEDEV
> - Default: LEBEDEV

## Expert General Wavefunction Info

### WFN

> Wavefunction type

> - Type: string
> - Possible Values: SCF
> - Default: SCF

## Expert Convergence Control/Stabilization

### FOLLOW_STEP_SCALE

> When using STABILITY_ANALYSIS = FOLLOW, how much to scale the step along the eigenvector by.

> - Type: double
> - Default: 0.5

## Expert Parallel Runtime

### DISTRIBUTED_MATRIX

> The dimension sizes of the distributed matrix

> - Type: array
> - Default: No Default

### PARALLEL

> Do run in parallel?

> - Type: boolean
> - Default: false

### PROCESS_GRID

> The dimension sizes of the processor grid

> - Type: array
> - Default: No Default

### TILE_SZ

> The tile size for the distributed matrices

> - Type: integer
> - Default: 512

## Expert Misc.

### SAPT

> Are going to do SAPT? If so, what part?

> - Type: string
> - Possible Values: FALSE, 2-DIMER, 2-MONOMER_A, 2-MONOMER_B, 3-TRIMER, 3-DIMER_AB, 3-DIMER_BC, 3-DIMER_AC, 3-MONOMER_A, 3-MONOMER_B, 3-MONOMER_C
> - Default: FALSE

## Expert DFSCF Algorithm

### DF_FITTING_CONDITION

> Fitting Condition

> - Type: double
> - Default: 1.0e-12

### DF_INTS_IO

> IO caching for CP corrections, etc

> - Type: string
> - Possible Values: NONE, SAVE, LOAD
> - Default: NONE

## Expert SAD Guess Algorithm

### SAD_CHOL_TOLERANCE

> SAD Guess Cholesky Cutoff (for eliminating redundancies).

> - Type: conv double
> - Default: 1e-7

### SAD_F_MIX_START

> SAD Guess F-mix Iteration Start

> - Type: integer
> - Default: 50

### SAD_MAXITER

> Maximum number of SAD guess iterations

> - Type: integer
> - Default: 50

### SAD_PRINT

> The amount of SAD information to print to the output

> - Type: integer
> - Default: 0

## Expert DFT

### DFT_BLOCK_MAX_POINTS

> The maximum number of grid points per evaluation block.

> - Type: integer
> - Default: 5000

### DFT_BLOCK_MAX_RADIUS

> The maximum radius to terminate subdivision of an octree block [au].

> - Type: double
> - Default: 3.0

### DFT_BLOCK_MIN_POINTS

> The minimum number of grid points per evaluation block.

> - Type: integer
> - Default: 1000

### DFT_BLOCK_SCHEME

> The blocking scheme for DFT.

> - Type: string
> - Possible Values: NAIVE, OCTREE
> - Default: OCTREE

### DFT_GRID_NAME

> The DFT grid specification, such as SG1.

> - Type: string
> - Possible Values: SG0, SG1
> - Default: No Default

### DFT_PRUNING_ALPHA

> Spread alpha for logarithmic pruning.

> - Type: double
> - Default: 1.0

### DFT_PRUNING_SCHEME

> Pruning Scheme.

> - Type: string
> - Possible Values: FLAT, P_GAUSSIAN, D_GAUSSIAN, P_SLATER, D_SLATER, LOG_GAUSSIAN, LOG_SLATER
> - Default: FLAT

### Navigation

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- PSI4 [beta5] »
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