I recently opened a topic about how to calculate the DOS of PE (polyethylene) -> Link: viewtopic.php?f=8&t=3188
This I could already succelsfully simulate with Abinint. Now i tried the same with PVA, but it failed.
I think it is because of the asymmetry of the monomer, and the fact that the initial coordinates have to be quite close to the real one otherwise it dose not congregate to the correct molecules.
First I tried it by simply change one H to OH... didn't congregate ...
Then I switched to relativ coordinates ... tried it with one monomer ...failed
Then I tried it with two monomers in one cell and oriented the OH groups contrary. ...but also this did not converged ...
How I proceeded last time for the PE:
1. relax with acell 0
2. vary acell fint min energy
3 relax with new acell
4 calculate DOS
(now I failed at step 1.)
Hier the input of the last try. (want to relax the atomic position) ...(cell size is from a paper... should be not too far from the real one)
Code: Select all
optcell 0
ionmov 2
ntime 1000
toldfe 1.5d-5
acell 5.04 6 6 angstrom
ntypat 3 natom 14 typat 2*1 1*2 4*3 2*1 1*2 4*3
xred
0 0 0
0.25 0 0.142
0.25 0.2 0.35
0 0.2 -0.2
0 -0.2 -0.2
0.25 -0.2 0.35
0.25 0.4 0.35
0.5 0 0
0.5 0 0.142
0.75 -0.2 0.35
0.5 0.2 -0.2
0.5 -0.2 -0.2
0.75 0.2 0.35
0.75 0.4 0.35
znucl 6 8 1 6 8 1 band 36
ecut 25
ecutsm 0.5
ngkpt 40 1 1
If any one has an idea how this could converge, I would be very thankful
thx
BR
maths
don't know why. Maybe I should use GAA instead of LDA, but it looks that bands are even to small.