[DFTB-Plus-User] simulation of a water box with periodic boundary conditions

[Bálint Aradi]

Dear Mingjun,

> 1. Because the hamitonian of sccdftb only includes interactions within a given cuttoff, I am not sure how dftbplus calculate the interaction from images under periodic conditions. Does it calculate electrostatic interaction by ewald method?

 DFTB+ includes the electrostatic interaction with all atoms in the
system via Ewald summation.

> 2. When non-periodic boundary condition is used, the interaction of atoms at the surface of the unit cell doesn't includes those from its nearest image. Do I understand it correctly?

 You do not have any unit cell, if non-periodic boundary conditions are
used. In contrast to many codes, DFTB+ calculates a real non-periodic
system, when you switch off periodic boundary conditions. Of course the
interaction between all atoms in the non-periodic system is calculated.

  Best regards,

  Bálint


-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b_aradi/


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