The NWChem Interface
Introduction
Interface to the NWChem program.
NWChem version 6.6 or later is required.
Command Line Arguments
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| basis |
keyword |
no |
STO-3G |
Required basis set (NWChem internal library) |
| basisspec |
Tcl List
|
no |
undefined |
basis set (ChemShell library) |
| charge |
integer |
no |
0 |
total charge |
| mult |
integer |
no |
1 |
Multiplicity (spin state) |
| list_option |
Output keyword
|
no |
medium |
how much output to generate |
| jobname |
string |
no |
nwchem |
name to use as root for file names |
| hamiltonian |
keyword |
no |
hf |
choice of QM Hamiltonian, (hf, blyp, b3lyp, lda, s-vwn) |
| accuracy |
keyword |
no |
medium |
DFT grid size: low, medium, high |
| itrscf |
integer |
no |
100 |
Maximum number of SCF iterations |
| dft_keywords |
string |
no |
none |
NWChem DFT keywords |
Directly linking NWChem into ChemShell
NWChem version 6.6 or later can be directly linked into ChemShell as a library. This may be essential
for parallel execution, depending on the platform you are running on.
NWChem should be compiled with USE_64TO32=y so that the library calls are
compatible with i4 ChemShell (alternatively, compile ChemShell with 8-byte
integers).
When compiling ChemShell, make sure the environment variables
NWCHEM_TOP and NWCHEM_TARGET are set so that ChemShell can locate the NWChem
code. ChemShell should be configured using the options
--with-mpi --with-ga={NWCHEM_TOP}/src/tools/install --with-nwchem (no path specified).
Parallel execution of NWChem via the directly-linked interface is supported in MPI builds of ChemShell.
Task-farming parallel calculations are also supported as of ChemShell 3.7.
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