ABINIT Discussion Forums

Hello,
i have done my berry phase calculation of polarization and according to its tutorial i wana to calculate born effectice charge. but i am confuzed by Omega in its ralation.
Z* = \Omega_0 (P[tau=+0.01] - P[tau=-0.01]) / (2*tau).would you please guide me about this parameter and about the dimenssion of born effective charge?
Best regards.
Mina

Omega_0 is the volume of the cell in it's ground state, as far as I know. If you want to know more about dynamical charge, please check out the physical review letter by Ghosez and Gonze titled "Dynamical atomic charges: the case of ABO3 compounds." Here's the link:

http://link.aps.org/doi/10.1103/PhysRevB.58.6224