[molpro-user] CBS extrapolations

[John Keith]

Thanks everyone for very quick and very insightful advice.  I'm glad I
asked these questions.  It'll take me a while to get through all the
literature suggestions, but I get the impression there is no single
"approved" way to do this, but its generally preferred to extrapolate
out both HF and correlation separately.

Kirk: I had already seen your 1994 JCP paper was comparing the L3 and
EX2 schemes over excel. Again, I got suspicious when the absolute CBS
values were a bit different (~0.003 Eh), but of course its the
relative energies that will be the most meaningful in the end.  If
this work ends up in a paper I'll report both schemes in my table.
Thanks for clarifying why Molpro's default is what it is.

Lorenzo: I'll definitely dig into your review. I actually only have
one paper on hand that talks about the benefits of CBS extrapolations
with total energies: JCP (2001), 115, 10438 (see text after eq. 6).
Given the responses today I'll take their suggestion with a grain of
salt.  :)

Mikael: Thanks for the literature.  This will also be very helpful.

Wanyi: Thanks for the tip! I managed to figure that much out on my own.  :)

Greetings from Ulm,

--john

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Ph D. John A. Keith
Institut für Elektrochemie     Email: john.keith at uni-ulm.de
Universität Ulm                    Telephone: +49-731-50-26061
Albert-Einstein-Allee 47       URL: http://www.wag.caltech.edu/home/johnk
Ulm D-89069                       URL:
http://www.uni-ulm.de/theo_echem/index.shtml
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In order to be an immaculate member of a flock of sheep, one must above all,
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--Albert Einstein (1879-1955)
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