Subject: SUMMARY: DFT & H-bonds

From: Didier MATHIEU <[email-masked]>
Date: Thu, 28 Jan 1999 13:02:30 +0000

Hi,

Many people asked me to summarize the replies to my question concerning
the performance of DFT, and especially early functionals such as
Becke-Perdew86, with regard to the description of the energetic of
H-bonds.

Much work appears to have been done on this subject as I got a lot of
references (Don't ask me already about their content, first I have to
plan a trip to Paris to get them... The "decentralisation" is not yet
effective with regard to libraries -). 

Clearly, everybody agree that hybrid functionals are better than GGA
functionals, the latter being themselves much better than LDA. Recently,
the team by Salahub has developped a LAP functional which performs well.
Somebody also pointed to the need for extended basis sets for
convergence.

With regard to the performance of early functionals, I retain from the
answers that the results provided by functonals such as BP for weak
bonds are fairly erratic.

Finally, in view of the wealth of answers pointing to new functionals,
especially hybrid ones, BP appears old-fashioned. 
In fact, we used this functional for the sake of comparison with
previous work, where we replaced BP geometries with molecular mechanics
MMFF structures.

Regards

-- 
Didier MATHIEU
CEA - Le Ripault, BP 16
37260 Monts (France)
Tel. 33(0)2.47.34.41.85