*LOCALIZATION

Performs molecular orbitals localization using the Pipek-Mezey criterion. The implementation uses an exponential parametrization and a Trus region minimization method instead of the Edminston-Ruedenberg algorithm. It works with the C₁symmetry and for the occupied orbitals.

.PRJLOC

Localization from projection analysis instead of Mulliken analysis. [Default: False]:

.PRJLOC

.OWNBAS

Calculate fragments in their own basis. For now it is the only option which can be used with projection analysis option (.PRJLOC) [Default: False]:

.OWNBAS

.VECREF

First give number of fragments to project onto. Then for each fragment give filename of MO coefficients and string specifying which orbitals will be used in the projection (Specification of orbital strings):

.VECREF
 3
 DFO1AT
 1..6
 DFH1AT
 1
 DFH2AT
 1

.HESLOC

Define model of the Hessian [Default: FULL].

Use full Hessian:

.HESLOC
 FULL

Use diagonal approximation of the Hessian. If using this approximation, there is danger of converging to the stationary point instead of minima:

.HESLOC
 DIAG

First the diagonal approximation of the Hessian will be used and after reaching convergence criterion the localization will switch to the construction of the full Hessian:

.HESLOC
 COMB

.CHECK

This keyword can be used only in combination with .HESLOC = COMB. The full Hessian will be calculated only at the last iteration. This way one can check if the procedure converged to the minimum.

.THFULL

Convergence threshold for the localization process. It applies on the functional value of the localization criteria when full Hessian is calculated. It is used in .HESLOC = FULL scheme and in the second part of the .HESLOC = COMB scheme. When not specified gradient criterion or criterion of the number of negative eigenvalues equals zero will be used:

.THFULL
 1.0D-13

.THGRAD

Convergence threshold for the localization process. It applies on the gradient of the localization functional. It is used in .HESLOC = FULL or DIAG scheme and in the second part of the .HESLOC = COMB scheme. When not specified the functional value criterion or criterion of the number of negative eigenvalues equals zero will be used:

.THGRAD
 1.0D-17

.THDIAG

Convergence threshold for the localization process. It applies on the functional value of the localization criteria when diagonal Hessian is calculated. It can be used with the .HESLOC = DIAG keyword. If .HESLOC = COMB it is used to switch from the first to the second stage of the convergence process:

.THDIAG
 1.0D-05

.SELECT

Select subset of MOs for localization (use Specification of orbital strings syntax). Currently only Pipek-Mezey localization is implemented, therefore localize only occupied orbitals. Localization of virtual orbitals is not recommended.

.SELECT
 1..5

.MAXITR

Maximum number of iterations. Default:

.MAXITR
 100

.PRINT

Set print level. Default:

.PRINT
 1