[Pw_forum] total force and number of k-points

[Elie Moujaes]

Dear all,
I have a simple question: does the total force acting on a system depend on the number of k-points  used? That is in my scf calculation I am using a grid of 4x4x1 for my system whereas the grid must be denser if phonon calculations are taking place I am using 8x8x1. Do I get different total force acting on the system and does it mean I have to relax the crystal twice one for an scf calculation and another for  a phonon calculation?
Thanks
Elie MoujawsUniversity of NottsUniversity ParkNG7 2RD
 		 	   		  
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