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Optimization of unit cell under stress.

Posted: Tue Jun 11, 2013 2:06 pm
by sunnyone
Dear All,

I am trying to optimize the unit cell of the attached compound but after some steps it stop and say :

chkdilatmx.F90:115:ERROR
The new primitive vectors rprimd (an evolving quantity)
are too large with respect to the old rprimd and the accompanying dilatmx :
this large change of unit cell parameters is not allowed by the present value of dilatmx.
You need at least dilatmx= 6.273783E+00
Action : increase the input variable dilatmx.
2.50000000000000E-01 2.50000000000000E-01 2.50000000000000E-01
Scale of Primitive Cell (acell) [bohr]
6.87606494930759E+01 6.87606494930759E+01 6.87606494930759E+01
Real space primitive translations (rprimd) [bohr]
0.00000000000000E+00 3.43803247465380E+01 3.43803247465380E+01
3.43803247465380E+01 0.00000000000000E+00 3.43803247465380E+01
3.43803247465380E+01 3.43803247465380E+01 0.00000000000000E+00
Unitary Cell Volume (ucvol) [Bohr^3]= 8.12755504378054E+04
Angles (23,13,12)= [degrees]
6.00000000000000E+01 6.00000000000000E+01 6.00000000000000E+01
Lengths [Bohr]
4.86211215353453E+01 4.86211215353453E+01 4.86211215353453E+01

so any one can help me?
the attached is my input file..


Best regards

Re: Optimization of unit cell under stress.

Posted: Tue Jun 11, 2013 2:17 pm
by ilukacevic
Hi!

Please, see the previous post in this forum section.

Also, does your SCF converge nicely?

Igor

Re: Optimization of unit cell under stress.

Posted: Sun Mar 22, 2015 4:19 am
by ftf-ahn
Dear Igor,


I have the same problem with rprimd being too large and that I get my calculations to crash with
this error and that I need to increase dilatmx, I am dealing with GaAs wurzite structure full geometry optimization.
I checked that my structure was correct by visualizing it.
it might seem silly but I sometimes change the initial cell size a bit, sometimes this rescues me.
my SCF calculations converges without any prob, but the geometry optimization does not converge...
Please help me.

Re: Optimization of unit cell under stress.

Posted: Mon Mar 23, 2015 8:43 am
by ilukacevic
Hi!

Please, see the old post first

http://forum.abinit.org/viewtopic.php?f=8&t=2185

Best regards,

Igor