CHGCAR difference for adsorbed molecules on slabs

[sibud]

Dear all,

First of all, I would like to thank you for this great forum.

I am interested to plot the charge density difference for a molecule adsorbed on metal slabs. In order to do that, I write a fortran code inspired from your script chargdiff.pl. The code is doing the difference as follow: [(CHGCAR-slab+molecule) - (CHGCAR-slab) - (CHGCAR-molecule)] and giving the difference as an (X, Y) file. However, I did the calculations twice but I am getting two diverged values in Y. I don't know if by using your script we could plot the charge difference.

Prof. Graeme comment on chargsum and chargdiff :

viewtopic.php?f=2&t=390

"In some files with very large (or small, maybe) charge densities, the fortran formatted numbers which are 5E18.11 can overflow their space and run into the previous number".

I don't know if my problem is related to this issue.

Any suggestions please ?

Best regards,
Sibud Jean