[DFTB-Plus-User] Problem of periodic structure optimization

[Max Ramirez G.]

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Dear list,

I use this thread to make another question.

On 11/05/2014 04:43 AM, Bálint Aradi wrote:
> Dear ??,
>
>>    I want to optimize a structure of two molecules absorbed on a
>> periodic TiO2 surface. But the structure of the periodic system cannot
>> converge after several steps. I changed my initial  configuration
>> several times, but the problem has not gone away. So I attach my input
>> files to seek help that whether the parameters are wrong.
>
> I can't see anything basically wrong with your input. Not sure, whether
> your structure is sensitive to that or not, but you could increase the
> electronic temperature to something like 100 K and try to make the
> SCCTolerance somewhat lower, let's say 1e-6.
>
>   Best regards,
>
>   Bálint

I have optimized one structure using the conjugate gradient method, and
afterwards I had used that optimized structure to optimize the box size,
using the LatticeOpt = Yes option.

What I understand is that using this option first is optimized the
structure and then the lattice. But if the structure is pre-optimized,
the firsts steps in the lattice optimization should be an optimization
of the lattice, and not from the structure, which is occurring in my
calculation. Actually, now the 23th step from the geometrical step is
running, and the lattice is not optimized yet. I'm doing something wrong?

Thanks in advance for your kind reply.

- -- 
Saludos,
Max Ramirez G.
<max.ramirez at gmail.com>
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