Prerequisites
MP3, MP4, CCSD and CCSD(T) calculations with the ccsdf12 module require the same
prerequisites as RICC2 calculations,

1.
 a converged SCF calculation with the oneelectron density threshold set to $denconv
1.d5 or less

2.
 an auxiliary basis defined in the data group $cbas

3.
 if orbitals should be excluded from the correlation treatment the data group $freeze
has to be set

4.
 the maximum core memory which the program is allowed to allocate should be
defined in the data group $maxcor; the recommended value is 66–75% of the available
(physical) core memory.

5.
 the data group $ricc2 with a specification of the coupledcluster model
Calculations with the CCSD(F12*) and CCSD(F12) methods require in addition:
 the data group $rir12 with the definition of the standard approximations for the
explicitlycorrelated contributions (see Sec. 9.5 for details)
 the data group $lcg, which define the correlation function (here it is in particular
important to choose for F12 calculations the exponent; recommended values are 0.9
for ccpVDZF12, 1.0 for ccpVTZF12 and 1.1 for ccpVQZF12 basis sets)
 a complementary auxiliary (CABS) basis set
Furthermore it is recommeded to select in addition an auxiliary JK basis set for the evaluation of
the Fock matrix elements. (The rijk menu of define can be used for this.)