This repository contains wrapper scripts compatible with the otool_external interface in ORCA.
The scripts call an external program, which computes the energy and gradient of a system,
then pass this information back to ORCA for use in optimization, NEB, GOAT, MD, etc.
The scripts should be put in some directory and made executable.
The interpreter required for each script (e.g. python) should be available the user environment.
A link named otool_external must be created in the ORCA executables directory,
which points to the chosen script.
Optional arguments are not supported, so additional wrappers or hard-coded modifications may be necessary.
In addition to the otool_external route which is backwards-compatible,
it is also possible to set the full path to the chosen scipt via the environment variable EXTOPTEXE,
or via the ORCA input:
%method
ProgExt "/full/path/to/script"
Ext_Params "optional command line arguments"
end
All scripts must be executable as:
scriptname <basename_EXT.extinp.tmp> [args]
where basename_EXT.extinp.tmp is the name of an input file generated
by ORCA (see below) and args are optional command line arguments.
The latter can be provided in the ORCA input file (starting with ORCA 6)
and are directly passed to the external script.
The extinp file has the following format:
basename_EXT.xyz # xyz filename: string, ending in '.xyz'
0 # charge: integer
1 # multiplicity: positive integer
1 # NCores: positive integer
0 # do gradient: 0 or 1
pointcharges.pc # point charge filename: string (optional)
Comments from # until the end of the line should be ignored.
The file basename_EXT.xyz will also be present in the working directory with standard XYZ format:
<NAtoms>
comment line
<Element> <X> <Y> <Z>
...
The script must generate a file called basename_EXT.engrad using the same basename as the XYZ file.
This file must have the following format:
#
# Number of atoms: must match the XYZ
#
3
#
# The current total energy in Eh
#
-5.504066223730
#
# The current gradient in Eh/bohr: Atom1X, Atom1Y, Atom1Z, Atom2X, etc.
#
-0.000123241583
0.000000000160
-0.000000000160
0.000215247283
-0.000000001861
0.000000001861
-0.000092005700
0.000000001701
-0.000000001701
In ORCA 5, exactly 3 comment lines must be present between entries (as above).
In ORCA 6, comments from # until the end of the line are ignored,
as are the (now optional) comment-only lines.
The script may also print relevant output to STDOUT and/or STDERR. STDOUT will either be printed in the ORCA standard output, or redirected to a temporary file and removed afterwards, depending on the type of job and ORCA output settings.