MOLPRO

47 POTENTIAL ENERGY SURFACES (SURF) 358
WHERE=value
DUMP=file name
EXTERN=file name
Restart=5600.2. Restarts using the RESTART option will fail
for broken SURF calculations, only restarts for finished SURF calculations
are possible. Note that, for restarting a calculation, you always
need to specify a SURF card. You cannot restart a calculation
simply beginning with a VSCF card, although the potential may be
completely available on record 5600.2.
In combination with the keywords DUMP and EXTERN for an external
restart file, the keyword WHERE specifies the path for the external
ASCII file. Two options are available, WHERE=home and WHERE=scr.
As the external files can be huge for SURF calculations, they will be
stored on the scratch disk given by the MOLPRO variable $TMPDIR
by default.
The potential can be dumped into an external ASCII-file which can be
used for restarting. Its name must be provided as the argument of the
DUMP keyword, e.g. DUMP=’formaldehyde.pot’. The ASCIIfile
provides the interface to other programs and offers the possibility
for controlled storage and modification of the computed potentials.
Dipole surfaces will also be dumped if available.
In principle, SURF calculations should be restartable at any point of a
truncated calculation. However, since only fully converged difference
potentials will be stored in the ASCII file (DUMP), this is not the case.
As a consequence, SURF calculations can be restarted from dumpfiles
once a batch of surfaces has been dumped. Since the generation
of the 2D or 3D surfaces usually requires about 2 to 3 batches, there
are about 6-10 restart points for surface calculation including 3D potentials.
Restarting from the ASCII dump-file is possible for any type
of VMULT calculation. As normal modes and harmonic frequencies
will also be read in from the external file, harmonic frequency calculations
need not to be repeated for such restarts.
47.4 Linear combinations of normal coordinates
LINCOMB,options
The LINCOMB directive allows for the calculation of linear combinations of normal coordinates
for the expansion of the potential. This is realized by 2x2 Jacobi rotations. At most 3N-6/2
rotations can be provided in the input.
NM1=n, NM2=m
ANGLE=value
Denote the two normal coordinates to be rotated.
Rotation angle in degree.
47.5 Scaling of individual coordinates
SCALNM,options
The SCALE option of the SURF program enables a modifaction of the extension of all difference
potentials by a common factor. In contrast to that the SCALNM directive allows for the scaling
with respect to the individual normal coordinates. This is the recommended choice for potentials
dominated by quartic rather than quadratic terms. At most 3N-6 individual scale factors can be
provided.