[Pw_forum] Charge Density

[Paul M. Grant]

I've been assuming the units of charge density as stored in *.save and used
in plotrho and accessed by xcrysden are scaled as (number of
electrons/angstroms^3), but just thought I'd better check.  Looking at the
codes, examples and tutorials available for PWscf, I couldn't find any
explicit confirmation (I'm sure there is somewhere) that this is indeed the
case.  I could try performing a volumetric integration on some simple
example, but thought I'd ask the community first.  It seems this is the case
just by looking at the contours and surfaces produced by xcrysden, but I'm
not too sure what the cryptic notation "delta n(r)" defines.  I take it's
the differential between isolevels in the units I've been using.

Also, some time ago (about three months!), I switched from espresso-3.2.3 to
o-sesame, and noticed that the charge density files in *.save are in a *.dat
binary format rather than *.xml.  What's going to be the future standard?

Finally, and I think I asked about this before, is there a developers guide
to the bowels of pw.x?  The makefile links an enormous number of object
files and I suppose one could figure this all out.  Surely, there have been
courses given at SISSA on its internal structure, if only in the shape of a
flow chart.  If these lectures are in Italian, no problem, and I would make
a translation available to all.

Ciao, -Paul

Paul M. Grant, PhD
Principal, W2AGZ Technologies
Visiting Scholar, Applied Physics, Stanford University
EPRI Science Fellow (Retired)
IBM Research Staff Member Emeritus
w2agz at pacbell.net
http://www.w2agz.com
 
 


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