$MP2

$MP2 group (relevant to SCFTYP=RHF,UHF,ROHF if MPLEVL=2)

Controls 2nd order Moller-Plesset perturbation runs, if requested by MPLEVL in $CONTRL. See also the DIRSCF keyword in $SCF to select direct MP2. MP2 is implemented for RHF, high spin ROHF, or UHF wavefunctions. Analytic gradients and the first order correction to the wave- function (i.e. properties) are available only for RHF. The $MP2 group is usually not given. See also $MCQDPT.

NCORE
= n Omits the first n occupied orbitals from the calculation. The default for n is the number of chemical core orbitals.

MP2PRP
= a flag to turn on property computation for RHF MP2 jobs with RUNTYP=ENERGY. This is appreciably more expensive than just evaluating the 2nd order energy correction alone, so the default is .FALSE. Properties are always computed during gradient runs, when they are an almost free byproduct.

LMOMP2
= a flag to turn on analysis of the MP2 energy in terms of localized orbitals. Any type of localized orbital may be used. This option is implemented only for RHF, and its selection forces use of the METHOD=3 transformation. The default is .FALSE.

The remaining parameters control execution characteristics

NWORD
= controls memory usage. The default uses all available memory. (default=0)

CUTOFF
= transformed integral retention threshold, the default is 1.0d-9.

METHOD
= n selects transformation method, 2 being the segmented transformation, and 3 being a more conventional two phase bin sort implementation. 3 requires more disk, but less memory. The default is to attempt method 2 first, and method 3 second.

AOINTS
= defines AO integral storage during conventional integral transformations, during parallel runs.
DUP stores duplicated AO lists on each node, and is the default for parallel computers with slow interprocessor communication, e.g. ethernet.
DIST distributes the AO integral file across all nodes, and is the default for parallel computers with high speed communications.


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