11.1.4 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

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.

FITDOM_MP2

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

FITDOM_CCSD

Similar to FITDOM_MP2 but used for LCCSD 2-ext transformation.

RDOMAUX_SCF

Distance criterion for fitting domain extension in SCF (default 5.0)

IDOMAUX_SCF

Connectivity criterion for fitting domain extension in SCF (default 0)

RDOMAUX_CORE

Distance criterion for core orbital fitting domain extension in SCF (default RDOMAUX_SCF).

IDOMAUX_CORE

Connectivity criterion for core orbital fitting domain extension in SCF (default IDOMAUX_SCF).

RDOMSCF_START

Distance criterion for fitting domain extension in the initial SCF iterations (default 3.0).

IDOMSCF_START

Connectivity criterion for fitting domain extension in the initial SCF iterations (default 1).

RDOMSCF_FINAL

Distance criterion for fitting domain extension in the final SCF iterations (default RDOMAUX_SCF).

IDOMSCF_FINAL

Connectivity criterion for fitting domain extension in the final SCF iterations (default IDOMAUX_SCF).

RDOMAUX_MP2

Distance criterion for fitting domain extension in LMP2. The default value depends on FITDOM_MP2

IDOMAUX_MP2

Connectivity criterion for fitting domain extension in LMP2. The default value depends on FITDOM_MP2

RDOMAUX_CCSD

Distance criterion for fitting domain extension in LCCSD. The default value depends on FITDOM_CCSD).

IDOMAUX_CCSD

Connectivity criterion for fitting domain extension in LCCSD. The default value depends on FITDOM_CCSD.

RDOMAUX_CPHF

Distance criterion for fitting domain extension in CPHF (default 3.0).

RDOMAUX_SCFGRD

Distance criterion for fitting domain extension in gradients (default 5.0).

SCSGRD

Switches the DF-LMP2 analytic gradient to Grimmes SCS scaled MP2 energy functional (default 0).