about DIPOL flag in Berry's phase calculations

Message

brocks · #1 Post by **brocks** » Sun Feb 04, 2007 9:24 am

Hi Forum,

i would like to use the Berry's phase method to calculate the spontaneous polarization of my system.
Following the manual about this kind of calculations i need
to set the DIPOL (3 values) by hand in INCAR.
I don't really understand if DIPOL is simply the center of mass of my system or the center of the unit cell.
How do i calculate the 3 numbers to put as values of this flag?
Thank you.

G.

Alenushka · #2 Post by **Alenushka** » Tue Feb 06, 2007 1:51 pm

Since it is no need to calculate the center of the unit cell (in fractional coordinates it is 0.5 0.5 0.5), it should be the center of mass. if you have cubic unit cell, no need to determine DIPOL flag.
http://cms.mpi.univie.ac.at/vasp/vasp/n ... car-dipol2

#3 Post by **admin** » Mon Feb 12, 2007 2:11 pm

it is neither the center of mass, nor the center of the cell, but the origin of the ionic contribution of the dipole moment.