General input for CC: *CC INPUT

In this section keywords for the coupled cluster program are defined. In particular the coupled cluster model(s) and other parameters common to all submodules are specified.

.B0SKIP

Skip the calculation of the $B0$-vectors in a restarted run. See comments under .IMSKIP.

.CC(2)

Run calculation for non-iterative CC2 excitation energy model (which is actually the well-known CIS(D) model).

.CC(3)

Run calculation for CC(3) ground state energy model.

.CC(T)

Run calculation for CCSD(T) (Coupled Cluster Singles and Doubles with perturbational treatment of triples) model.

.CC2

Run calculation for CC2 model.

.CC3

Run calculation for CC3 model.

.CCD

Run calculation for Coupled Cluster Doubles (CCD) model.

.CIS

Run calculation for CI Singles (CIS) method.

.CCR(3)

Run calculation for CCSDR(3) excitation energy model.

.CCS

Run calculation for Coupled Cluster Singles (CCS) model.

.CCSD

Run calculation for Coupled Cluster Singles and Doubles (CCSD) model.

.CCSTST

Test option which runs the CCS finite field calculation as a pseudo CC2 calculation. CCSTST disables all terms which depend on the double excitation amplitudes or multipliers. This flag must be set for CCS finite field calculations.

.DEBUG

Test option: print additional debug output.

.E0SKIP

Skip the calculation of the $E0$-vectors in a restarted run. See comment under .IMSKIP.

.F1SKIP

Skip the calculation of F-matrix transformed first-order cluster amplitude responses in a restarted run. See comment under .IMSKIP.

.F2SKIP

Skip the calculation of F-matrix transformed second-order cluster amplitude responses in a restarted run. See comment under .IMSKIP.

.FIELD

READ (LUCMD,*) EFIELD
READ (LUCMD,'(1X,A8)') LFIELD

Add an external finite field (operator label LFIELD) of strength EFIELD to the Hamiltonian (same input format as in Sec. 24.2.8). These fields are only included in the CC calculation and not in the calculation of the SCF reference state (i.e. the orbitals). Using this option in the calculation of numerical derivatives thus gives so-called orbital-unrelaxed energy derivatives, which is standard in coupled cluster response function theory. Note that this way of adding an external field does not work for models including triples excitations (most notably CCSD(T) and CC3). For finite field calculations of orbital-relaxed energy derivatives the field must be included in the SCF calculation. For such calculations, use the input section *HAMILTONIAN (Sec. 24.2.8).

.FREEZE

READ (LUCMD,*) NFC, NFV

Specify the number of frozen core orbitals and number of frozen virtuals (0 is recommended for the latter). The program will automatically freeze the NFC(NFV) orbitals of lowest (highest) orbital energy among the canonical Hartree-Fock orbitals. For benzene a relevant choice is for example 6 0.

.FROIMP

READ (LUCMD,*) (NRHFFR(I),I=1,MSYM)
READ (LUCMD,*) (NVIRFR(I),I=1,MSYM)

Specify for each irreducible representation how many orbitals should be frozen (deleted) for the coupled cluster calculation. In calculations, the first NRHFFR(I) orbitals will be kept frozen in symmetry class I and the last NVIRFR(I) orbitals will be deleted from the orbital list.

.FROEXP

READ (LUCMD,*) (NRHFFR(I),I=1,MSYM)
DO ISYM = 1, MSYM
IF (NRHFFR(ISYM.NE.0) THEN
READ (LUCMD,*) (KFRRHF(J,ISYM),J=1,NRHFFR(ISYM))
END IF
END DO
READ (LUCMD,*) (NVIRFR(I),I=1,MSYM)
DO ISYM = 1, MSYM
IF (NVIRFR(ISYM.NE.0) THEN
READ (LUCMD,*) (KFRVIR(J,ISYM),J=1,NVIRFR(ISYM))
END IF
END DO

Specify explicitly for each irreducible representation the orbitals that should be frozen (deleted) in the coupled cluster calculation.

.FRSKIP

Skip the calculation of the F-matrix transformed right eigenvectors in a restarted run. See comment under .IMSKIP.

.HERDIR

Run coupled cluster program AO-direct using HERMIT (Default is to run the program only AO integral direct if the DIRECT keyword was set in the general input section of DALTON. IF HERDIR IS NOT SPECIFIED THE ERI PROGRAM IS USED AS INTEGRAL GENERATOR.)

.IMSKIP

SKIP THE CALCULATION OF SOME RESPONSE INTERMEDIATES IN A RESTARTED RUN. THIS OPTIONS AND THE FOLLOWING SKIP OPTIONS IS PRIMARILY FOR VERY EXPERIENCED USERS AND PROGRAMMERS WHO WANT TO SAVE A LITTLE BIT OF CPU TIME IN RESTARTS ON VERY LARGE CALCULATIONS. IT IS ASSUMED THAT THE USER KNOWS WHAT HE IS DOING WHEN USING THESE OPTIONS, AND THE PROGRAM DOES NOT TEST IF THE INTERMEDIATES ARE THERE OR ARE CORRECT. THE RELEVANT QUANTITIES ARE ASSUMED TO BE AT THE CORRECT DIRECTORY AND FILES. THESE COMMENTS ALSO APPLIES FOR ALL THE OTHER SKIP OPTIONS FOLLOWING!

.L0SKIP

SKIP THE CALCULATION OF THE ZEROTH-ORDER GROUND-STATE LAGRANGE MULTIPLIERS IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.L1SKIP

SKIP THE CALCULATION OF THE FIRST-ORDER RESPONSES OF THE GROUND-STATE LAGRANGE MULTIPLIERS IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.L2SKIP

SKIP THE CALCULATION OF THE SECOND-ORDER RESPONSES OF THE GROUND-STATE LAGRANGE MULTIPLIERS IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.LESKIP

SKIP THE CALCULATION OF LEFT EIGENVECTORS IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.LISKIP

SKIP THE CALCULATION OF (IAJB) INTEGRALS IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.M1SKIP

SKIP THE CALCULATION OF THE SPECIAL ZEROTH-ORDER LAGRANGE MULTIPLIERS FOR GROUND-EXCITED STATE TRANSITION MOMENTS, THE SO-CALLED -VECTORS, IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.MAX IT

READ (LUCMD,'(I5)') MAXITE

MAXIMUM NUMBER OF ITERATIONS FOR WAVE FUNCTION OPTIMIZATION (DEFAULT IS MAXITE = 40).

.MAXRED

READ (LUCMD,*) MAXRED

MAXIMUM DIMENSION OF THE REDUCED SPACE FOR THE SOLUTION OF LINEAR EQUATIONS (DEFAULT IS MAXRED = 200).

.MP2

RUN CALCULATION FOR SECOND-ORDER MØLLER-PLESSET PERTURBATION THEORY (MP2) METHOD.

.MXDIIS

READ (LUCMD,*) MXDIIS

MAXIMUM NUMBER OF ITERATIONS FOR DIIS ALGORITHM BEFORE WAVE FUNCTION INFORMATION IS DISCARDED AND A NEW DIIS SEQUENCE IS STARTED (DEFAULT IS MXDIIS = 8).

.MXLRV

READ (LUCMD, *) MXLRV

MAXIMUM NUMBER OF TRIAL VECTORS IN THE SOLUTION OF LINEAR EQUATIONS. IF THE NUMBER OF TRIAL VECTORS REACHES THIS VALUE, ALL TRIAL VECTORS AND THEIR TRANSFORMATIONS WITH THE JACOBIAN ARE SKIPPED AND THE ITERATIVE PROCEDURE FOR THE SOLUTION OF THE LINEAR (I.E. THE RESPONSE) EQUATIONS IS RESTARTED FROM THE CURRENT OPTIMAL SOLUTION.

.NOCCIT

NO ITERATIONS IN THE WAVE FUNCTION OPTIMIZATION IS CARRIED OUT.

.NSIMLE

READ (LUCMD, *) NSIMLE

SET THE MAXIMUM NUMBER OF RESPONSE EQUATIONS THAT SHOULD BE SOLVED SIMULTANEOUSLY. DEFAULT IS 0 WHICH MEANS THAT ALL COMPATIBLE EQUATIONS (SAME EQUATION TYPE AND SYMMETRY CLASS) ARE SOLVED SIMULTANEOUSLY.

.NSYM

READ (LUCMD,*) MSYM2

SET NUMBER OF IRREDUCIBEL REPRESENTATIONS.

.O2SKIP

SKIP THE CALCULATION OF RIGHT-HAND SIDE VECTORS FOR THE SECOND-ORDER CLUSTER AMPLITUDE EQUATIONS IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.PAIRS

DECOMPOSE THE SINGLES AND/OR DOUBLES COUPLED CLUSTER CORRELATION ENERGY INTO CONTRIBUTIONS FROM SINGLET- AND TRIPLET-COUPLED PAIRS OF OCCUPIED ORBITALS. PRINT THOSE PAIR ENERGIES.

.PRINT

READ (LUCMD,'(I5)') IPRINT

SET PRINT PARAMETER FOR COUPLED CLUSTER PROGRAM (DEFAULT IS TO TAKE THE VALUE IPRUSR, SET IN THE GENERAL INPUT SECTION OF DALTON).

.R1SKIP

SKIP THE CALCULATION OF THE FIRST-ORDER AMPLITUDE RESPONSES IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.R2SKIP

SKIP THE CALCULATION OF THE SECOND-ORDER CLUSTER AMPLITUDE EQUATIONS IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.RESKIP

SKIP THE CALCULATION OF THE FIRST-ORDER RESPONSES OF THE GROUND-STATE LAGRANGE MULTIPLIERS IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.

.RESTART

TRY TO RESTART THE CALCULATION FROM THE CLUSTER AMPLITUDES, LAGRANGE MULTIPLIERS, RESPONSE AMPLITUDES ETC. STORED ON DISK.

.SOPPA(CCSD)

WRITE THE CCSD SINGLES AND DOUBLES AMPLITUDES ON THE SIRIUS INTERFACE FOR LATER USE IN A SOPPA(CCSD) CALCULATION. THIS CHOOSES AUTOMATICALLY THE COUPLED CLUSTER SINGLES AND DOUBLES (CCSD) MODEL.

.THRENR

READ (LUCMD,*) THRENR

SET THRESHOLD FOR CONVERGENCE OF THE GROUND STATE ENERGY.

.THRLEQ

READ (LUCMD,*) THRENR

SET THRESHOLD FOR CONVERGENCE OF THE RESPONSE EQUATIONS.

.X2SKIP

SKIP THE CALCULATION OF THE INTERMEDIATES (NEEDED TO BUILD THE RIGHT-HAND SIDE VECTORS FOR THE SECOND-ORDER GROUND STATE LAGRANGE MULTIPLIER RESPONSE EQUATIONS) IN A RESTARTED RUN. SEE COMMENT UNDER .IMSKIP.