Re: CCL:Why aren't DFT methods suitable for long distance interactions?

Dear Yubo Fan and CCL readers,
 I agree with the opinion of  Lou Noodleman. DFT in the form of gradient
 corrected potentials (GGA) has
 proved suitable for many applications involving H-bonds. (LSDA is not
 suitable).
 I would like to add one probably important success of GGA-ACM-DFT: the
 description of OH...O interactions in sugar molecules.
 The following paper discusses some details:
 G.I. Csonka et al: Chem. Phys. Lett. 257 (1996) 49-60.
 futher references can be found on my home page.
 It is also true that that quite weak H-bonds are difficult for DFT. Weak
 long range Van der Waals interactions
 (dispersion energies) are missing from DFT.
 Walter Kohn was working on dispersion energies within DFT framework
 (DFT97, Wienna). Also John Perdew had some interesting papers about the
 long range interactions.
 Gabor I. Csonka              Budapest University of Technology
 FAX: (361) 463.36.42         Inorganic Chemistry Dept. Ch. Bldg
 csonka -8 at 8- web.inc.bme.hu        H-1111, Bp. Szent Gellert ter 4
 http://web.inc.bme.hu/~csonka/csg.html
 http://www.ch.bme.hu/inc/csg.html