MOLPRO

10 MOLECULAR GEOMETRY 61
LINESTYLE,style1, style2,...
Line styles to be used for columns 1,2,...; omit to use default
values.
9.3 Diatomic potential curve analysis
For the case that a table contains one or more potential energy functions for a diatomic molecule,
with the first column containing bond lengths in Bohr or Ångstrom, it is possible to calculate
spectroscopic constants using
DIATOMIC[,DEGREE=n][,MASS=m][,PRINT=p]
The data are fitted to a polynomial of degree n (default is number of points minus 1, ie interpolation),
and spectroscopic constants calculated using reduced mass m expressed in u. Note that it is
possible to constrain which bond lengths are used through the use of the RANGE subcommand.
10 MOLECULAR GEOMETRY
10.1 Geometry specifications
The geometry may be given in standard Z-matrix form, or XYZ form. The geometry specifications
are given in the form
[SYMMETRY, options ]
[ORIENT, options ]
[ANGSTROM]
GEOMETRY={
atom specifications
}
GEOMETRY must come after the other commands that modify the way the geometry is constructed.
The following are permitted as SYMMETRY options:
NOSYM
Any valid combination of symmetry generators, as described in
section 10.2 below.
Disable use of symmetry. Instead of SYMMETRY,NOSYM also
just NOSYM can be used.
The following are permitted as ORIENT options:
CHARGE
MASS
NOORIENT
SIGNX=±1
Orient molecule such that origin is centre of charge, and axes
are eigenvectors of quadrupole moment.
Orient molecule such that origin is centre of mass, and axes are
eigenvectors of inertia tensor (default for Z-matrix input). Alternatively,
the symmetry centre can be specified as CENTRE=MASS|CHARGE.
Disable re-orientation of molecule (default for XYZ-input).
Force first non-zero x-coordinate to be positive or negative, respectively.
Similarly, SIGNY, SIGNZ can be set for the y- and