MOLPRO

15 DENSITY FITTING 96
LOCFIT F12
LOCFIT CCSD
LOCFIT 2EXT
LOCFIT 3EXT
LOCFIT 4EXT
LOCFIT CPHF
LOCFIT SCFGRD
If positive, use local fitting in DF-LMP2-F12 (default LOCFIT)
If positive, use local fitting in DF-LCCSD (default LOCFIT)
If positive, use local fitting in LCCSD 2ext transformation (default
LOCFIT CCSD)
If positive, use local fitting in LCCSD 3ext transformation (default
LOCFIT CCSD)
If positive, use local fitting in LCCSD 4ext transformation (default
LOCFIT CCSD)
If positive, use local fitting in CPHF (default LOCFIT)
If positive, use local fitting in gradient calculations (default
LOCFIT)
LOCORB If positive, use localized orbitals in DF-HF (default 1)
LOCTRA
If positive, use local screening in first half transformation (default
LOCFIT).
DSCREEN If positive, enable density screening in LMP2 (default 0)
KSCREEN
If positive, enable fit-basis Schwarz screening in LMP2 (default
depends on LOCTRA).
15.1.4 Parameters for fitting domains
The following options can be used to modify the domains used in local fitting. These parameters
only have an effect if LOCFIT=1. The local fitting domains are determined in two
steps: first primary orbital domains are deterimined. In the LMP2 and LCCSD programs, the
primary orbital domains are the same as used for excitation domains and determined by the
Boughton-Pulay procedure, as described in Sect. 29. Depending on the value of FITDOM MP2
or FITDOM CCSD for LMP2 and LCCSD, respectively, either the orbital domains are used directly
or united pair domains are generated. In DF-HF the primary orbital domains include all
basis functions at atoms which have Löwdin charges greater or equal to THRCHG SCF. In the
second step the primary fitting domains are extended using either distance criteria (RDOMAUX,
in bohr) or bond connectivity criteria (IDOMAUX). IDOMAUX=1 means to include all functions
at atoms wich are at most one bond distant from the primary domains. By default, distance
criteria are used. However, if IDOMAUX.ge.0, the distance criteria are ignored and connectivity
is used.
THRCHG SCF
FITDOM MP2
FITDOM CCSD
RDOMAUX SCF
Parameter to select the primary orbital domains in local exchange
fitting (default 0.1). All atoms are include which have
L”owdin charges greater than this value. The primary domains
are extended according to RDOMAUX SCF or IDOMAUX SCF.
Parameter to select primary fitting domains in LMP2 transformation
(default 3). 1: use orbital domains; 2: use united orbital
domains of strong pairs; 3: use united orbital domains of strong
and weak pairs (default 3). The primary domains are extended
according to RDOMAUX MP2 or IDOMAUX MP2
Similar to FITDOM MP2 but used for LCCSD 2-ext transformation.
Distance criterion for fitting domain extension in SCF (default
5.0)