[CPMD-list] Binding energy of water dimer with CPMD

[Juerg Hutter]

Hi

we have recently

Molecular Dynamics Simulation of Liquid Water: Hybrid Density Functionals
T. Todorova, A. P. Seitsonen, J. Hutter, I-F. W. Kuo, C. J. Mundy;
J. Phys. Chem. B 110 3685 - 3691 (2006)
http://dx.doi.org/10.1021/jp055127v

published the following numbers for a water dimer

B3LYP PW MT-PP for BLYP    : 4.63 Kcal/mol
Gaussian 6-311++G(3df,2p)  : 4.53 Kcal/mol

the BSSE error in the Gaussian calculation was 0.29 Kcal/mol.
Other reference calculation can be found in the book by
Koch and Holthausen "A Chemists Guide to DFT". There you
can also find the values for the BSSE for all kind of
basis sets.

regards

Juerg Hutter

----------------------------------------------------------
Juerg Hutter                   Phone : ++41 44 635 4491
Physical Chemistry Institute   FAX   : ++41 44 635 6838
University of Zurich           E-mail: hutter at pci.unizh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
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On Sun, 12 Nov 2006, Pradip K Biswas wrote:

> Hi,
> I was doing some test calculation for the binding energy of a water dimer using the following
> realtion:
> 
> E_B = 2*E_T(H2O) - E_T(2H2O)
> 
> where E_T(H2O) is the total energy output of CPMD for a water molecule and E_T(2H2O) is the
> same for a water dimer. Using MT pp and B3LYP, I get E_B~4.44 Kcal/mol; (for BLYP I get
> E_B~4.0) compared to a 6-311+G(d,p) Gaussian basis DFT result of E_B~5.83 Kcal/mol. Am I
> doing anything wrong with CPMD or is this what I can expect with a plane-wave based DFT? I'll
> greatly appreciate any in-depth answer to the problem.
> 
> regards,
> Pradip.
> 
>