:orphan: .. index:: *LOCALIZATION .. _*LOCALIZATION: ============== \*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 *C*\ :sub:`1`\ symmetry and for the occupied orbitals. .. index:: .PRJLOC .. _LOCALIZATION_.PRJLOC: .PRJLOC ------- Localization from projection analysis instead of Mulliken analysis. [Default: False]:: .PRJLOC .. index:: .OWNBAS .. _LOCALIZATION_.OWNBAS: .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 .. index:: .VECREF .. _LOCALIZATION_.VECREF: .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 (:ref:`orbital_strings`):: .VECREF 3 DFO1AT 1..6 DFH1AT 1 DFH2AT 1 .. index:: .HESLOC .. _LOCALIZATION_.HESLOC: .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 .. index:: .CHECK .. _LOCALIZATION_.CHECK: .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. .. index:: .THFULL .. _LOCALIZATION_.THFULL: .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 .. index:: .THGRAD .. _LOCALIZATION_.THGRAD: .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 .. index:: .THDIAG .. _LOCALIZATION_.THDIAG: .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 .. index:: .SELECT .. _LOCALIZATION_.SELECT: .SELECT ------- Select subset of MOs for localization (use :ref:`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 .. index:: .MAXITR .. _LOCALIZATION_.MAXITR: .MAXITR ------- Maximum number of iterations. Default:: .MAXITR 100 .. index:: .PRINT .. _LOCALIZATION_.PRINT: .PRINT ------ Set print level. Default:: .PRINT 1