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)