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

INPUT OPTIONS

       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)
                  ) )

                                                  5 June, 1998                                           geom(1)