[Pw_forum] charge density

[Paolo Giannozzi]

alan chen wrote:

>        I want to know how the charge density is normalized in PWSCF.

it is not "normalized": it has the value it should have. Just
notice that it does NOT include the charge -e: the "true" charge
density is -e*rho

>        For example, I have calculated bulk STO. The integral of charge 
> density over the unit cell is 0.162.  I normalize it to the total number
> of electron which is 40.

the (correct) integral of the charge density over the unit cell is 40.
In real space, the integral is (sum over grid points)*(volume element).
The volume element is the volume of the cell (omega) divided by the
number of grid points (nr1*nr2*nr3). In G-space, the integral is
simply omega*rho(G=0).

P.
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy