Subject: Gradient corrections again

From: Andrew Horsfield <[email-masked]>
Date: Fri, 17 Mar 2000 14:28:54 +0000 (GMT)

Hi,

Having taken a look at some gradient correction papers, there are a couple
of features that strike me. The first if the complexity of evaluating the
exchange-correlation potential, and hence the need for tricks to stabilise
the numerics - at least on FFT meshes. The second is the importance of
fitting. This leads to my questions:

1) Has anyone developed an alternative non-local scheme that produces
   smoother potentials than the gradient corrections (some weighted
   density scheme seems an obvious choice - the only examples of this I
   have seen appear to be worse than LDA).

2) Has anyone tried fitting an LDA form in the same way that GGA forms are
   fitted, just to see what happens? If so, what are the results like?

Cheers,

Andrew

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From: Alexander Hofmann <[email-masked]>
Date: Fri, 17 Mar 2000 17:26:39 +0100 (CET)

>    have seen appear to be worse than LDA).

Hi Andrew,

as I remember, Schwerdtfeger, New Zealand, did some work on other or
improved gradient correcetions to LDA. I've heard only a lesson about it,
I've not seen a paper (because I did not look for).

Alex

---

Dr. Alexander Hofmann
Institut fuer Angewandte Chemie Berlin-Adlershof e.V.
Richard-Willstaetter-Str. 12

D-12489 Berlin

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