DIRRCI – Direct CI module

Relativistic RASCI module written by Lucas Visscher

This section allows for Kramers unrestricted relativistic Configuration Interaction calculations, Ref. [MOLFDIR].

Note that when the namelist GOSCIP – COSCI module is also present in the input, GOSCIP will be called instead of DIRRCI !

The input should be given in namelist form.

&CIROOT – Select the state to converge on

IREPNA

Abelian symmetry group of the desired state(s).

Default: First abelian symmetry in the list

NROOTS

Number of states to optimize on.

Default:

NROOTS=1

Advanced options

ISTART

Start vector method.

COSCI start vectors:

ISTART=1

Determinant with lowest eigenvalue:

ISTART=2

First (reference) determinant:

ISTART=3

If the COSCI start vectors are not available, then the default will be 2.

NSEL(NROOTS)

Rank number of states to be optimized.

Default:

NSEL=1,2,3,...

SELECT

Select wave functions on basis of largest overlap with the start wave function.

Default:

SELECT=F

&DIRECT – Convergence control

CONVERE

Convergence threshold for energy.

Default:

CONVERR=1.0D-9

MAXITER

Maximum number of direct CI iterations.

Default:

MAXITER=10

Advanced options

CONVERR

Convergence threshold for residual vector.

Default:

CONVERR=1.0D-10

RESTART

Restart on CI-vectors present in MRCFINV.

Default:

RESTART=F

CPUMAX

Maximum amount of CPU-seconds to be used.

Default:

CPUMAX=604800

&LEADDET – Analyze the CI wave function

Advanced options

GETDET

Get the list of dominant determinants.

Default:

GETDET=T

COMIN

Print contributions of determinants only if the square of the coefficients is larger than COMIN.

Default:

COMIN=0.1

&OPTIM – Fine tuning of the algorithm

Programmers options

IGENEX

Write coupling coefficients to file (default):

IGENEX=2

Calculate coupling coefficients when needed:

IGENEX=1

&RASORB – Specify the type of CI and the active space

NELEC

Number of electrons (excluding frozen core electrons).

Default:

NELEC=0

NRAS1

Number of spinors in the RAS1 space for each abelian irrep.

Default:

NRAS1=NSYMRP*0

NRAS2

Number of spinors in the RAS2 space for each abelian irrep.

Default:

NRAS2=NSYMRP*0

MAXH1

Maximum number of holes in RAS1 spinors.

Default:

MAXH1=0

MAXE3

Maximum number of electrons in RAS3 spinors.

Default:

MAXE3=0

&CIFOPR – Specify different options in CI Property Module

PROPER

Activate the property module to evaluate expectation values of One-electron operators defined inside

PRPTRA under MOLTRA, over the DIRRCI wavefunction [Nayak2006], [Nayak2007], [Nayak2009].

Default:

PROPER=F

NEOPER

Define the number of property operators one needs to calculate expectation values.

Default:

NEOPER=0

NAMEE

Mention the names of One-electron operators as defined inside PRPTRA.

For example, Electric dipole moment and magnetic hyperfine structure constants

can be defined as follows. Of coures, the given names are users own choice.

NAMEE='Z-DIP','X1-HYP','Y1-HYP','Z1-HYP'