MOLPRO

10 MOLECULAR GEOMETRY 67
x1,y1,z1,q1,flag1
.
xN,yN,zN,qN,flagN
The x,y and z fields stand for the point charge coordinates (in Å), q for its charge and flag=1
indicates that gradients should be computed for this lattice point (0 means no gradient).
outfile specifies a file name to which the lattice gradient is written; if blank, it will be written to
the output stream.
VARGRAD
NUCONLY
REMOVE
(logical) Stores the lattice gradient in variable VARGRAD.
(logical) Disables gradient evaluation with respect to the lattice,
independent of flag in the lattice file.
(logical) Removes the lattice.
Symmetry is not supported for lattice gradients.
10.6 Redefining and printing atomic masses
The current masses of all atoms can be printed using
MASS, PRINT
The atomic masses can be redefined using
MASS, [type,] [symbol=mass, . . . ]
The optional keyword type can take either the value AVER[AGE] for using average isotope
masses, or ISO[TOPE] for using the masses of the most abundant isotopes. This affects only
the rotational constants and vibrational frequencies. As in most quantum chemistry packages,
the default for type is AVERAGE. If INIT is given, all previous mass definitions are deleted and
the defaults are reset.
Individual masses can be changed by the following entries, where symbol is the chemical symbol
of the atom and mass is the associated mass. Several entries can be given on one MASS card,
and/or several MASS cards can follow each other. The last given mass is used.
Note that specifying different isotope masses for symmetry related atoms lowers the symmetry
of the system if the molecular centre of mass is taken as the origin. This effect can be avoided
by using the charge centre as origin, i.e., specifying CHARGE as first entry in the GEOMETRY
input:
GEOMETRY={CHARGE; ...}
10.7 Dummy centres
DUMMY,atom1,atom2,...
Sets nuclear charges on atoms 1,2 etc. to zero, for doing counterpoise calculations, for example.
atom1, atom2,... can be Z-matrix row numbers or tag names. Note that the current
setting of dummies is remembered by the program across restarts via the MOLPRO variable
DUMMYATOMS. Dummies can be reset to their original charges using a DUMMY card with no