the question of structure optimization

Queries about input and output files, running specific calculations, etc.


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weizz
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Joined: Mon Mar 26, 2007 1:18 am

the question of structure optimization

#1 Post by weizz » Mon Jun 25, 2007 12:02 am

hi ,
when I optimized structure, the calculation was interrupted.
I find the following output in the out file.

WARNING: Sub-Space-Matrix is not hermitian in DAV
5.080957515206845E-005

I copy the CONTCAR to POSCAR to continue the calculation,but it interrupted again. the warning is similar.
the INCAR was:
general:
SYSTEM = clean W(100) surface
ENCUT = 315
EDIFFG= -0.02
ISMEAR = 2 ; SIGMA = 0.2
dynamic:
IBRION = 2
NSW = 200
POTIM = 0.1

how i can eliminate the warning and calculate correctly ??


thanks
Last edited by weizz on Mon Jun 25, 2007 12:02 am, edited 1 time in total.

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the question of structure optimization

#2 Post by admin » Tue Jun 26, 2007 9:06 am

Most often, these errors are related to unreasonable ionic structures. Therefore please check if that error occured at the first ionic step (input POSCAR (and the interatomic NN distances listed in OUTCAR) ) or at some later step of the relaxation history (XDATCAR).
If the error occured at the first ionic step although the geometry input was reasonable, please check if the k-point mesh was sufficient (have you converged it properly for the bulk optimization?).
if the error occured at some later ionic step, please have a look if the error persists if you choose a different ionlc relaxation algorithm (like damped MD).
Last edited by admin on Tue Jun 26, 2007 9:06 am, edited 1 time in total.

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