MOLPRO

29 LOCAL CORRELATION TREATMENTS 215
ICLOSE
IWEAK
IDIST
IVDIST
KEEPCL
(default 1) Strong pairs are separated by less that ICLOSE bonds.
Close orbital pairs are separated by at least ICLOSE bonds but less
than IWEAK bonds.
(default 2) Weak orbital pairs are separated by at least IWEAK bonds
but less than IDIST bonds.
(default 5) Distant orbital pairs are separated by at least IDIST bonds
but less than IVDIST bonds.
(default 8) Very distant orbital pairs (neglected) are separated by at
least IVDIST bonds.
(default 0) If KEEPCL=1, the LMP2 amplitudes of close pairs are
included in the computation of the strong pair LCCSD residuals. If
KEEPCL=2 all close pairs are fully included in the LCCSD (this does
not affect the triples list). This option is not yet implemented as efficiently
as it could, and can therefore lead to a significant increase of
the CPU time.
Setting RCLOSE or RWEAK to zero means that all pairs up to the corresponding class are treated
as strong pairs (RWEAK=0 implies RCLOSE=0). For instance, RCLOSE=0 means that strong
and close pairs are fully included in the LCCSD (in this case KEEPCL=1 has no effect). Note,
however, that setting RCLOSE=0 increases the length of the triples list. Setting RDIST=0 means
that all distant pairs are treated as weak pairs. This does not affect RWEAK and RCLOSE and
has no effect unless multipole approximations are used for distant pairs. Setting RVDIST=0
means that no very distant pairs are neglected. Again, this has no effect on the other distance
parameters.
29.8 Directives
29.8.1 The LOCAL directive
The LOCAL directive can be used to specify options for local calculations. If this directive
is inside the command block of a local calculation, the options are used only for the current
calculation, and this is entirely equivalent as if they were specified on the command line. The
LOCAL directive can also be given outside a command block, and in this case the options are
used for all subsequent local correlation calculations in the same input.
Example:
DF-LMP2,THRBP=0.985
is equivalent to
{DF-LMP2
LOCAL,THRBP=0.985}
In the following example the LOCAL directive is global and acts on all subsequent local calculations,
i.e. both calculations will use THRBP=0.985
LOCAL,THRBP=0.985
DF-LMP2 !local MP2 calculation
OPTG
!geometry optimization using the DF-LMP2 energy
DF-LCCSD(T) !local coupled cluster at the optimized structure.