[Pw_forum] ld1.x Questions

Lorenzo Paulatto paulatto at sissa.it
Fri Jan 18 10:28:23 CET 2008

On Thu, January 17, 2008 22:20, Paul M. Grant wrote:
> 1)	What is the purpose of the "negative ocs(nl)" settings one sees
> frequently in the input files in /atomic_doc/pseudo_library? (not covered
> that I can see in INPUT_LD1)  It doesn't seem to make physical sense.

Orbitals with negative occupation are excluded from the all-electron
calculation; you need to do this when they are unbounded.

Putting a negative occupation means: I don't really want to compute this
orbital, but I'd like to use it's label later for a specific orbital
identified by an arbitrary, but well defined, reference energy, and L and
M indexes.

There is probably a more formal way to say that.

> 2)	Why doesn't this library contain some transition metal examples?

The examples in the library are the pseudopotentials that Andrea Dal Corso
(and only he) has done during the years. There are a few transition metals
among them in the CVS version.

> 3)	I've observed ld1.x from O-sesame (CVS) performs much better the
> executable in the present distribution  espresso-3.2.3, which yields a
> number of formatting errors.

There have been a few improvements on that front recently, nothing should
really change but the number of things that can will cause crashes has
been reduced a bit. Keep in mind that "input files which produce a good
pseudo" are a tiny subset of "input files which doesn't cause a crash."

> 4)	It's stated that ld1.x output can be plotted with Grace, but I see
> no options to produce or launch .agr files such as exists in Opium.  I
> guess it has to be done "by hand."

I think you are right.

> -Paul

Lorenzo Paulatto
+39 040 3787 511

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