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[Marek Veithen <Marek.Veithen@ulg.ac.be>]

Aaron Deskins wrote:

Hello Marek,
   I had a question in regards to the following message that you posted a while ago on the abinit forum. The particular change you mentioned (making diag smaller) seems to only apply when using optcell not equal to 0. Would you have any suggestions what I should change in the code if I'm using optcell = 0?

thank you,

Aaron
 
 

Dear Aaron,

I don't have much experience in this case. Up to now, I was able to relax
the atomic positions using either ionmov = 2 or 3 without changing any ABINIT
routine.

There was only one special case: the value of boxcut obtained from the default
grid in ABINIT was too small and I had to increase ngfft by hand in the input file
in order to obtain accurate forces for the structural relaxation.

But even if optcell = 0 you can initialize the inverse hessian by hand
simply by creating a _HES file. I have newer used this option and I don't
know where it is documented on the ABINIT web page. But if you look inside
the routine brdmin.f, you will find all informations abtout the format of the _HES
file.

Best regards,

Marek
 

-- 
Marek VEITHEN
Universite de Liege
Institut de Physique, Bat. B5
Allee du 6 aout, 17
B- 4000 Sart Tilman
BELGIUM

Phone : ++(32) (0)4-366.36.12
Fax   : ++(32) (0)4-366.29.90
E-mail: Marek.Veithen@ulg.ac.be