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["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Hi,
You've just dicovered  the so called equilibrium lattice parameter.
Would the function be monotonic it would means that the structure
under consideration either collapse spontaneously or explode. Which is
quite not an appropriate behavior for neutral atoms. Right ?
regards
PMA


On 4/16/07, Hongyi Zhao <hongyi.zhao@gmail.com> wrote:
> Hi all,
>
> I am wondering Why the Etotal has the parabola-function-relationship in
> respect to the increasment of the parameter *acell*?  For detail of my
> problem, I describe it as follows:
>
> The input file for abinit is like this:
>
> -----------------
> ndtset   15
> acell:   9.6  9.6  9.6
> acell+   0.1  0.1  0.1
> kptopt   1
> ngkpt   6  6  6
> toldfe   1.0d-6
> iscf   5
> nstep   15
> diemac   12.0
> ecut   9.0
> enunit   2
> nband   5
> ixc   1
> typat   1  1
> znucl   14
> natom   2
> rprim   0.0  0.5  0.5
>        0.5  0.0  0.5
>       0.5  0.5  0.0
> xred   0.0  0.0  0.0
>       0.25 0.25 0.25
> -----------------
>
> Then, I find that the the Etotal has the parabola-function-relationship
> in respect to the increasment of the parameter *acell*, in detail, the
> Etotal will take its minimum vaule when the *acell* is about 10.2 bohr.
> Dut to my poor theoretical background, I can't understand this
> phenomena.  Who can give me some hints on this thing?
>
> Thanks in advance.
>
> ---
> Hongyi Zhao
> GnuPG DSA: 0xD108493B


--
Pierre-Matthieu Anglade