[QE-users] How to Calculate Charge Density Difference

[Guido Fratesi]

Dear Sherifdeen,


you can compute the density ".charge" files for other parts of the 
system (e.g., your C atom and O atom, separately, or whatever you wish) 
then run again pp.x with input like:

&INPUTPP
!! EMPTY
/
&PLOT
   nfile = 3
   filepp(1)='CO-all.charge'
   filepp(2)='C.charge'
   filepp(3)='O.charge'
   weight = 1, -1, -1
... the rest follows


You can subtract whatever .charge files have been generated, provided 
they are consistent. Atoms are read from the first file (filepp(1)).


For plotting the isosurface, you may use xcrysden, need output_format=3 
(--> output.xsf)

Kindly see www.xcrysden.org for information about this software.


Hope this helps.

Guido



-- 
Guido Fratesi

Dipartimento di Fisica
Universita` degli Studi di Milano
Via Celoria 16, 20133 Milano, Italy