The ORCA Interface
Introduction
This interface supports energy and gradient evaluations with the
ORCA electronic structure package.
Make sure that the ORCA directory is in your $PATH before using the
ORCA interface.
Command Line Arguments
Method
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| hamiltonian |
keyword |
no |
HF |
Choice of QM Hamiltonian (currently hf and dft are supported). |
| functional |
keyword |
no |
undefined |
Choice of DFT functional. |
| gridsize |
integer |
no |
undefined |
DFT integration grid size (0-7). ORCA default is 2. |
| use_finalgrid |
Boolean
|
no |
undefined |
Use "multigrid" feature (a larger
integration grid for final energy and gradient evaluation). ORCA default is yes. |
| finalgridsize |
integer |
no |
undefined |
Final DFT integration grid size. ORCA default is 4. |
| use_ri |
Boolean
|
no |
no |
Use RI approximation.
If yes, an auxiliary basis set must be specified using auxbasis. |
| d3 |
Boolean
|
no |
no |
Add Grimme's D3 dispersion correction. |
Basis set
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| basis |
keyword |
no |
STO_3G |
Basis set (from the ORCA internal library). See note 1. |
| newgto |
Tcl List
|
no |
undefined |
Additional basis sets for named atoms from the ORCA internal library.
Specify as { { Cu TZVPP } { ... } }. |
| basisspec |
Tcl List
|
no |
undefined |
Basis set specification (using the ChemShell library) |
| ecpspec |
Tcl List
|
no |
undefined |
ECP specification (using the ChemShell library) |
| auxbasis |
keyword |
no |
undefined |
Auxiliary basis set for the RI approximation. |
SCF control
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| scftype |
keyword |
no |
RHF |
Wavefunction type (RHF, UHF, ROHF). |
| guess |
keyword |
no |
undefined |
Choice of initial guess, e.g. HCore, Hueckel,
PAtom (ORCA default: PAtom). Ignored for restart calculations.
|
| direct |
Boolean
|
no |
yes |
Integral handling. If direct, recompute integrals at each
iteration (rather than storing them on disk). |
| convergence |
keyword |
no |
NormalSCF |
SCF convergence criterion. (NormalSCF, StrongSCF, TightSCF etc. - see Orca manual) |
| maxcyc |
integer |
no |
undefined |
Number of SCF cycles permitted. |
Molecule properties
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| charge |
integer |
no |
0 |
Total charge (of QM system) |
| mult |
integer |
no |
1 |
Multiplicity (spin state) |
Excited state calculations
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| excited |
Boolean
|
no |
no |
Perform an excited state calculation (CIS or TDDFT depending on the hamiltonian). |
| estate |
integer |
no |
1 |
The excited state of interest (1 is the 1st excited state, etc.) |
| eroots |
integer |
no |
= estate |
Number of excitations to calculate. Only
needs to be set if you want to calculate further states above estate
(e.g. to avoid root flipping). |
| tda |
Boolean
|
no |
yes |
Use the Tamm-Dancoff approximation (TDDFT only). See note 2. |
General options
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| optstr |
string |
no |
undefined |
Additional ORCA input. Useful for specifying ORCA options not covered explicitly by this interface. |
| list_option |
Output keyword
|
no |
medium |
How much output to generate |
| jobname |
string |
no |
orca1 |
Name to use as root for ORCA file names |
| restart |
Boolean
|
no |
no |
Restart ORCA calculation from a previous wavefunction. |
| moinp |
string |
no |
save.gbw |
Name of a .gbw file to restart from (see note 3). |
| executable |
string |
no |
orca |
ORCA executable (see note 4). |
| version |
real |
no |
4.0 |
ORCA version number. Used to determine how to specify basis sets (See note 1). |
| nproc |
integer |
no |
1 |
Number of processors for parallel execution (see note 4). |
Notes
- Basis sets should be specified using the format used in the "%basis" section
of ORCA input files. As of ORCA v4.0, this is identical to basis keywords on the "simple input" line.
To use the old format set the version option to e.g. 3.0. In this case some common basis set names
are translated to the old format by the interface (see the orca.tcl file).
- ORCA's default is to use the Tamm-Dancoff approximation. As of v2.8 full TDDFT is not supported either for hybrid functionals or for gradient calculations with any functional.
- Do not specify moinp=$jobname.gbw. According to the ORCA v2.8 manual this will not work as $jobname.gbw will be overwritten on startup.
- If you run ORCA in parallel (using nproc) you must
specify the full path to ORCA with the executable option.
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