Dear Ren,
it is not possible to obtain a good interlayer
interaction with PBE. Check the literature and you will find that more many
VDW interactions is repulsive. LDA may give some acceptable results but just
by a fortuitous error cancelation.
All the DFT methos fails when they predict the VDW interactions at long
distances (4-6 Angstrom) on only a few of them give bonded complexes near
the VDW minimum.
You will find a good discussion in journal of Chemical theory and
computation 3 289.
Good luck!
Pablo
----- Original Message -----
From: "Ren Hao" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, April 04, 2008 2:11 PM
Subject: [SIESTA-L] Posible SPAM: How to calculate the interlayer inter
actions of graphite using SIESTA?
Dear all,
I'm trying to relax the geometry structure of graphite. The intralayer
structures are ok, but the best interlayer distance I got is about 7.5
angstrom, which is ~12% larger than the experimental value(6.7 Ang).
PBE functional and DZP basis for carbon is used in the calculation.
Is there anyone has some suggestions on the calculation of van der Walls
interactions between graphite layers?
I would appreciate any help and advice!
--
Hao Ren
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