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Frozen Density Embedding calculations using the FDE script

The shell script FDE controls and executes automatically FDE calculations. The script FDE prepares the input files (running define), runs the calculations (only dscf is supported in the present versiob), and combines the results (running fdetools). Because the FDE equations are coupled sets of one-electron equations (one for each subsystem), full relaxation of the electron densities of both subsystems is obtained by using a freeze-and-thaw [142] procedure until convergence.
The converged FDE calculations are store in the subdirectories STEPN/SUBSYSTEM_A and STEPN/SUBSYSTEM_B, where N is the number of the FDE iteration. The subdirectory ISOLATED_SUBSYSTEM_A and ISOLATED_SUBSYSTEM_B contain instead the calculations for isolated subsystems (see also Section 15.2.1).

Current functionalities and limitations of FDE are:

In order to perform a FDE calculation, the files coord and control for the total system are necessary to take informations on atomic coordinates and basis sets. The input file for the total system can be generated, as usual, with define but no calculation on the total system is required. $denconv 1.d-7 option should be defined in file control in order to better converge the embedded densities and better describe the dipole moment.

Given a closed-shell supramolecular system with a GGA/LDA exchange-correlation functional, the command

                        FDE -p 3
invokes an iterative resolution of the KSCED equations with revAPBEk [145,146] as approximation of the non-additive kinetic potential (see Eq. 15.5) in the monomolecular basis set approach. The two subsystems are defined via an integer m = 3 in the example above which identifies the first atom of the subsystem B in the file coord of the supramolecular system with n atoms, where the atoms 1…m - 1 belong to the subsystem A while the atoms mn to the B one. Thus the file coord must contains first all the atoms of the system A and then all the atoms of the system B.

As an example we report here the FDE -p 3 output for the HF dimer:

                           FDE  Version 1.02
                 Frozen Density Embedding Main Driver

                          Scf-like procedure for 
                closed-shell interacting systems (dimers)
 
                 program development: Savio Laricchia
                                      Eduardo Fabiano
                                      Fabio Della Sala
 
          S. Laricchia, E. Fabiano, L. A. Constantin, F. Della Sala, 
          J. Chem. Theory Comp. (2011)     
          S. Laricchia, E. Fabiano, F. Della Sala, 
          J. Chem. Phys. 133, 164111 (2010) 
          L. A. Constantin, E. Fabiano, S. Laricchia, F. Della Sala, 
          Phys. Rev. Lett. 106, 186406 (2011) 
          S. Laricchia, E. Fabiano, F. Della Sala, 
          Chem. Phys. Lett. 518, 114 (2011) 
 
                   Sun Mar 25 23:00:01 CEST 2012
 
Monomolecular basis set approach...

Serial calculation will be performed...
running /home/fabiods/REDO/branch64/TURBOMOLE/bin/em64t-unknown-linux-gnu/dscf

b-lyp exchange-correlation potential in KS supermolecular calculation...
revapbek kinetic energy approximation will be used...
Default convergence criterion on the system dipole: 0.005
Default value of starting damping parameter is 0.45
Default value of step damping parameter is 0.10
Default value of maximum damping parameter is 0.90
Default value of maximum fde iterations  is 20
Saving options in fde.input
 
  +-----------------------------------------------------------+
  | Subsystem A atomic coordinates and basis set information  |
  |  x        y       z      atom    basis set         ecp    |
  +-----------------------------------------------------------+
 
  2.5015  -0.1705  -0.0000     f    def2-TZVP         none
  3.2889   1.3859   0.0000     h    def2-TZVP         none
 
  +-----------------------------------------------------------+
  | Subsystem B atomic coordinates and basis set information  |
  |  x        y       z      atom    basis set         ecp    |
  +-----------------------------------------------------------+
 
 -2.7537   0.0364  -0.0000     f    def2-TZVP         none
 -1.0191  -0.1789   0.0003     h    def2-TZVP         none

Running Isolated subsystems:
 
************************
* ISOLATED SUBSYSTEM A *
************************
Done!
 
************************
* ISOLATED SUBSYSTEM B *
************************
Done!

Saved isolated subsystems data in:
isolated_energy.ks
mos_A.ks
mos_B.ks
 
*********************
*   FDE - step 1    *
*********************
 
FDE ENERGY (TOTAL SYSTEM):            -200.96417090754 Ha
FDE BINDING ENERGY:                      5.865327 mHa
                                         3.680548 kcal/mol
Dipole convergence: 0.138071,  Damping: 0.45
 
*********************
*   FDE - step 2    *
*********************
 
FDE ENERGY (TOTAL SYSTEM):            -200.96418098234 Ha
FDE BINDING ENERGY:                      5.875401 mHa
                                         3.686870 kcal/mol
Dipole convergence: 0.009246,  Damping: 0.35
 
*********************
*   FDE - step 3    *
*********************
 
FDE ENERGY (TOTAL SYSTEM):            -200.96418289036 Ha
FDE BINDING ENERGY:                      5.877309 mHa
                                         3.688067 kcal/mol
Dipole convergence: 0.004395,  Damping: 0.25

 See embedded susbsystems calculations in:
  STEP3/SUBSYSTEM_A
  STEP3/SUBSYSTEM_B
 See total system in:
  STEP3/ENERGY_SYSTEM
 
                   Sun Mar 25 23:00:21 CEST 2012
                   Total time: 20 secs.

The final energies are stored in the file fde_energy. The directory STEPN/ENERGY_SYSTEM contains the total system with density ρA + ρB; this directory can (only) be used for density analysis.



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