NAME¶
geom - analyzes a molecular geometry input in Cartesian coordinates.
DESCRIPTION¶
The program
geom reads a set of Cartesian coordinates and determines from
them the bond distances (Bohr and angstrom), bond angles, torsional angles,
out-of-plane angles (optional), moments of inertia, and rotational constants.
FILES REQUIRED¶
input.dat - Input file
and one of the following:
geom.dat - geometry file
file11.dat - PSI-format geometry/gradient file
FILES GENERATED¶
geom.out - file containing the analysis
The
geom program has the following options:
- -h
- Print help information (these options).
- -aces [filename]
- Read the input in an ACES output format, with each line
consisting of atomic symbol, atomic number, and Cartesian coordinates (in
Bohr). The optional argument is the name of the geometry input file, which
defaults to geom.dat.
- -qchem [filename]
- Read the input in an QCHEM output format, with each line
consisting of the atom number, the atomic symbol, and Cartesian
coordinates (in Angstroms). The optional argument is the name of the
geometry input file, which defaults to geom.dat.
- -xyz [filename]
- Read the input in an XYZ output format. The first line
contains the number of atoms and the second line is a comment line.
Subsequent lines each contain the atomic symbol and Cartesian X Y and Z
coordinates (in Angstroms). The optional argument is the name of the
geometry input file, which defaults to geom.dat.
- -oop
- Print out-of-plane angles, where the angle a-b-c-d is
defined as the angle formed by the vector a-d and the plane defined by
atoms b, c, and d.
- DO_OOP = boolean
- Same as command-line switch -oop described above.
- ISOTOPES = matrix of reals/strings
- Used to specify masses to be used in the calculation of the
center of mass and rotational constants. One array is provided for each
isotopomer to be calculated. The arrays can mix floating point numbers
with strings which designate isotopes. If this array is not given and
file11.dat is present, then the masses will be obtained by converting the
atomic numbers in file11. If masses are not given by ISOTOPES or by
file11, then no mass-related quantities will be calculated.
- -g [filename]
- Read Cartesian coordinates from a file other than
file11.dat. If a filename is not given, the default is geom.dat. The
alternative file is assumed to be in a format similar to that of PSI's
geom.dat. Since such files do not contain atomic numbers, the moments of
inertia and rotational constants are not calculated if this option is
used.
- READ_GEOM = boolean
- This option in input.dat tells geom to read the
geometry from geom.dat in the PSI geom.dat format.
- -a
- Print parameters for all pair distances.
- PRINT_ALL_DIST = boolean
- Same as -a flag described above.
- -d distance
- Only print parameters involving pairs of atoms which are
less than distance bohr apart (default value is 4.0 bohr).
- PRINT_DISTANCE = value
- Same as -d flag described above.
- -angstrom
- The input coordinates are in angstroms, not bohr.
- ANGSTROM = boolean
- If TRUE, the input coordinates are in angstroms
instead of bohr. The default is FALSE.
The following example is for calculating the geometrical information for
water with several different isotopes. The geometry is read from geom.dat
rather than from file11.dat.
geom: (
read_geom = true
isotopes = (
(O H H)
(O D D)
(O18 1.007825 1.007825)
) )