NEB-CI Distances rep too large

[nat zip]

Hello CP2K users,

I am doing a fluoride ion transport NEB-CI calculation with 2x2x2 LaF3, a known fluoride ion conductor. The calculation runs, but the distances between the replicas are larger than the length of the ion transfer in question (the distance between the two fluoride atoms is only 2.79 Å). The energy differences are also very high (up to 5.5eV below).

 *******************************************************************************
 BAND TYPE                     =                                          CI-NEB
 BAND TYPE OPTIMIZATION        =                                            DIIS
 STEP NUMBER                   =                                              46
 NUMBER OF NEB REPLICA         =                                               6
 DISTANCES REP =        2.425611        3.015968        4.084716        3.955761
                        4.362458
 ENERGIES [au] =    -5003.850194    -5003.807430    -5003.704672    -5003.685870
                    -5003.696118    -5003.835012
 BAND TOTAL ENERGY [au]        =                           -30022.53790402270897

 *******************************************************************************

Any help with this would be appreciated.

Thanks,

Kyle

[Marcella Iannuzzi]

Dear Kyle

By a quick look into your initial and final structures, it seems to me that you wrongly swapped atom 170 and 171. 
Regards

Marcella 

[nat zip]

Dear Marcella,

Thank you for your response. I am unsure about what you mean by wrongly swapped. Atom 171 in the initial file is missing in the final and atom 170 of the final is missing in the initial to create the initial and final replicas of the ion transport. Or am I setting it up wrong?

Regards

Kyle

[Marcella Iannuzzi]

Yes there is something wrong.

NEB uses a one to one connection among the atoms of the configurations along the band. Atom 171 of the initial configuration moves over a path connecting it to atom 171 in the final configuration. 

Respectively, atom 170 in the initial configuration transforms into atom 170 in the final configuration. 

The displacement is calculated between atoms with the same index.

 

 F   -3.623374   10.455758   12.465138   ====>  F   -3.623374   10.455758   12.465138

 F   -3.622812    6.273323   12.973153    ====>   F   -3.622812    6.273323   12.973153

La    8.380952    6.273449    9.266408   ====>   La    8.380952    6.273449    9.266408

 F    3.621311   10.456022    8.758477   ====>    F    6.087493    6.654405    8.013106           ∂R  = 4.59237666132189117935

 F    3.621868    6.273578    9.266634   ====>     F    3.621311   10.456022    8.758477          ∂R  = 4.21320088056978360828

Regards

Marcella

 

 

[nat zip]

Dear Marcella,

This fixed the problem. Thank you for your input.

Regards

Kyle