Table of contents
Details
The MOLECULE
input section specifies the molecular information: such as
geometry, (approxmiate) spin multiplicity, and charge. The MOLECULE
section is
a required section for all ChronusQ jobs.
Keywords
Keyword | Type | Description | Required? | Default |
---|---|---|---|---|
CHARGE |
Signed Integer | Overall molecular charge (in electrons) | Yes | N/A |
MULT |
Unsigned Integer | Approximate spin multiplicity | No | 0 |
GEOM |
Multiline String | Geometry specification from input file (in Angstroms) | Yes if READGEOM is INPUTFILE
|
N/A |
READGEOM |
String | Location of geometry specification (INPUTFILE or FCHK ) |
No | INPUTFILE |
GEOM
Keyword
The The GEOM
keyword provides the specification for the position and identity of all atoms in the system. It is a multiline keyword, meaning it expects data to be provided as indented lines after the declaration. The data lines for the GEOM
keyword are in the format:
ATOMIC_SYMBOL POSITION_X POSITION_Y POSITION_Z
Currently, only cartesian coordinates in Angstroms are available. As an example, take this specification of the geometry of ammonia:
geom:
N -0.00000 0.00000 0.00000
H 1.01733 -0.06831 -0.01031
H -0.31160 -0.66357 0.70776
H -0.31160 -0.38951 -0.89427
Note that the geometry must be indented relative to the GEOM
keyword.
READGEOM
Keyword
The Location to retrieve geometry. Either INPUTFILE
(default) or FCHK
.
ChronusQ currently supports reading geometry specification from a Gaussian formatted checkpoint file. If this is desired, set READGEOM
to FCHK
. You must also specify the formatted checkpoint file on the invocation of ChronusQ. (See Running ChronusQ)
-
INPUTFILE
: Geometry specification in ChronusQ input file (see example below)- The
GEOM
keyword must also be specified.
- The
-
FCHK
: Geometry specification in fhck file from the Gaussian software package- The
GEOM
keyword will be ignored. - Atoms are assumed to be the default isotope.
- The
Example
[Molecule]
charge = 0
mult = 3
geom:
O 0. 0. 0.608586
O 0. 0. -0.608586