[Pw_forum] using pp.x to calculate psi^2

[Paolo Giannozzi]

On Wed, 2013-04-03 at 22:32 +1100, Hongze Xia wrote:

> As far as I know, psi can be defined as psi = c(n,k)*exp(-i r*k)
> where c(n,k) is not a function of position r

No: psi(r) = \sum_k c(n,k)*exp(-i r*k)

> By this definition, psi^2 = c*(n,k)c(n,k) is a real number 
> independent of r. 

No: what is calculated is |psi(r)|^2, not what you have written.

> Can anyone tell me what is the unit of psi (or c(n,k)) in QE? 

all quantities are in atomic (Rydberg) units unless explicitly
specified, so psi(r) is in (bohr radii)^(-3/2)

> Another question is that if I plot a 1D plot of the spherical average
> of psi^2, does it matter if choosing a different starting point and
> plotting line?

the starting point matters, the plotting line doesn't

>  The last question is that where I can find the total number of kband
> and kpoint? 

in the output of pw.x

> If kpoint is manually set up in pwscf input file instead of using a k
> mesh-grid, does it have the same sequence as the one in that input
> file?

the index "kpoint" refers to the sequence of k-points as it appears in
the output

P.
-- 
 Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
 Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
 Phone +39-0432-558216, fax +39-0432-558222