[CPMD-list] water structure

[Juerg Hutter]

Hi
> Hi,
> I'm testing calculations for dipole moments with the help of Wannier
> centers. The optained
> dipole moment calculated so far is 1.88 D.
> Now I have a question concerning the structure of water. I get 0.963 A
> and a angle of 105.75 degree.
> In literature I see 104.5 from CPMD calculations. Is the optained one
> 105.75 too big?

This might be due to the positioning of the molecule within the grid,
different convergence criteria, FE vs. normal DFT, different GC-Cutoff
values etc.
As long as you are not sure that you have absolutely the same
parameters, I would consider this difference not important.

>
> I use FEMD with BLYP functional,  gc-cutoff of 1.0e-7 and a energy
> cutoff of 70 Ry.
> Is it sufficient or do I should use another functional?

You don't need FEMD for simple water calculations. Only use FEMD for
systems with no or very small band gap.

regards

Juerg Hutter


>
> regards,
> Christian
>
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