From Diracwiki

Contents 1 DIRAC-styleinput 2 **RELCC 2.1 .FOCKSP 2.2 .ENERGY 2.3 .GRADIENT 2.4 .NELEC 2.5 .NEL_F1 2.6 .NEL_F2 2.7 .PRINT 2.8 .DEBUG 2.9 *CCENER 2.9.1 .DOMP2 2.9.2 .MAXIT 2.9.3 .MAXDIM 2.9.4 .NTOL 2.9.5 .NOSING 2.9.6 .NODOUB 2.10 *CCFOPR 2.11 *CCFSPC 2.11.1 .DOIH 2.11.2 .DOEA 2.11.3 .DOIE 2.11.4 .DOEA2 2.11.5 .DOIE2 2.11.6 .DOEXC 2.11.7 .NACTH 2.11.8 .NACTP 2.11.9 .MAXIT 2.11.10 .MAXDIM 2.11.11 .NTOL 2.12 *CCIH 2.12.1 .EHMIN 2.12.2 .EHMAX 2.12.3 .EPMIN 2.12.4 .EPMAX

DIRAC-styleinput

The old namelist style input used up to DIRAC10 is replaced by an input that is more consistent with the rest of the input. In DIRAC11 it is possible to use both styles of inputs but we have the intention to phase out the namelist input in upcoming releases.

**RELCC

Specification of reference determinant, type of calculation, and general settings.

.FOCKSP

Activate the Fock space module. This option should be used for multireference calculations. See further CCFSPC

.ENERGY

Activate the energy calculation. This is the preferred option for calculations on closed shell or simple open shell systems.

Default:

No energy calculation.

.GRADIENT

Calculate the effective 1-particle density matrix (currently only for a closed shell MP2 wave function). This option can be used to calculate molecular properties.

Default:

No gradient calculation.

.NELEC

Specify the occupation of the reference determinant (both for CC and FSCC calculations). More information can be found here: NELEC

.NEL_F1

Number of electrons in the gerade irreps of the Abelian symmetry group. See also NELEC_F1

.NEL_F2

Number of electrons in the ungerade irreps of the Abelian symmetry group. See also NELEC_F2

.PRINT

Print level.

Default:

.PRINT
 0

.DEBUG

Print debug information.

Default:

Debug information is not printed.

*CCENER

Covers options related to energy.

.DOMP2

Calculate the MP2 energy.

.MAXIT

Set maximum number of iterations allowed to solve the CC equations.

.MAXDIM

Set maximum number of amplitude vectors used in the DIIS extrapolation.

.NTOL

Specify requested convergence (10^-NTOL) in the amplitudes.

.NOSING

Eliminate T1 amplitudes in the calculation (only interesting for test purposes, this gives no computational speed-up).

.NODOUB

Eliminate T2 amplitudes in the calculation (only interesting for test purposes, this gives no computational speed-up).

*CCFOPR

Calculate first-order properties (expectation values) for the MP2 wave function.

*CCFSPC

Perform a Fock space MRCC calculation in which a model space is correlated and then diagonalized to give CC energies for a set of states.

.DOIH

Use the Intermediate Hamiltonian formalism in which an auxiliary space is used to prevent the "intruder state" problem. Default: IH formalism not used.

.DOEA

Calculate electron affinities (add one electron to the reference state, allowing occupation of the active virtual orbitals)

.DOIE

Calculate ionization energies (remove one electron from the reference state, allowing depletion of the active occupied orbitals)

.DOEA2

Calculate second electron affinities (add two electrons to the reference state, allowing occupation of the active virtual orbitals)

.DOIE2

Calculate second ionization energies (remove two electrons from the reference state, allowing depletion of the active occupied orbitals)

.DOEXC

Calculate excitation energies (allow excitation from the set of active occupied orbitals to the set of active virtual orbitals)

.NACTH

Specification of the set of active hole orbitals (from which ionization/excitation takes place)

.NACTP

Specification of the set of active particle orbitals (to which electron attachment/excitation takes place)

.MAXIT

Maximum number of iterations allowed to solve the FSCC equations

.MAXDIM

Set maximum number of amplitude vectors used in the DIIS extrapolation.

.NTOL

Specify requested convergence (10^-NTOL) in the amplitudes.

*CCIH

Options for intermediate hamiltonian in FSCC.

.EHMIN

Minimum orbital energy of occupied orbitals forming the auxiliary (Pi) space. Orbitals with energies lower than this energy are taken in the secundary (Q) space and do not contribute to the model space.

.EHMAX

Maximum orbital energy of occupied orbitals forming the auxiliary (Pi) space. Orbitals with energies higher than this energy are taken in the primary (Pm) space.

.EPMIN

Minimum orbital energy of virtual orbitals forming the auxiliary (Pi) space. Orbitals with energies lower than this energy are taken in the primary (Pm) space.

.EPMAX

Maximum orbital energy of virtual orbitals forming the auxiliary (Pi) space. Orbitals with energies higher than this energy are taken in the secundary (Q) space and do not contribute to the model space.