Dear Korir<br><br>First of all you are going from A to B !! but A and B are too different from each other. For a TS structure only few atoms change their locations compared to the reactant or product. Also are you sure that you have already set the atomic numbers the same as each other for A and B ?<br>
<br>you can fix 80-90 percent of atoms during the NEB calculation for the first steps also you should use "no-CI" and then "auto".<br><br>Oxygen is a spin polarized atom !! why didn't you consider that ? you need to use nspin=2 and a value for starting_magnetization.<br>
<br><br>In some cases 28 for the cutoff is not sufficient. <br><br>Overall I think that the first step to figure it out is checking your structure and then the details that I have mentioned. <br><br>I hope it helps.<br><br>
Best Wishes, m<br><br> <br> <br><br><br>----------------------------------------<br>Masoud Nahali<br>SUT<br>
<a href="mailto:masoud.nahali@gmail.com" target="_blank">masoud.nahali@gmail.com</a> <br><a href="http://alum.sharif.edu/%7Em_nahali" target="_blank">alum.sharif.edu/~m_nahali</a> <div><br><br></div><br><br><br><br><font>Date: Sun, 18 Nov 2012 23:38:07 +0100<br>
Korir wrote:<br><br>Dear QE community,<br>
I am interested in studying oxygen vacancy diffusion in ZnO and for
this reason I performed neb calculation using the input attached, but
for some reasons I don't understand, the system does not converge even
though the initial and final states optimized beforehand. Furthermore,
the choice of vacancy position were made in such that they correspond
to first neighbor oxygen atoms in ZnO. Attached are input and output
files.<br><br>
Kindly assist in addressing this problem.</font>
<font><br><br><br>
Regards</font>
<font><br>
Korir Kiprono<br>
Polytechnic of Turin<br>
Italy<br><br><br>
BEGIN</font>
<font><br>
BEGIN_PATH_INPUT<br>
&PATH<br>
restart_mode = 'from_scratch'<br>
string_method = 'neb',<br>
nstep_path = 400,<br>
ds = 1.D0,<br>
opt_scheme = "broyden",<br>
num_of_images = 11,<br>
k_max = 0.1D0,<br>
k_min = 0.05D0,<br>
first_last_opt = .true.,<br>
CI_scheme = "auto",<br>
path_thr = 0.05D0,<br>
/<br>
END_PATH_INPUT<br>
BEGIN_ENGINE_INPUT<br>
&CONTROL<br>
prefix = "ZnO_Ovac",<br>
outdir = "./tmp",<br>
pseudo_dir = "./",<br>
/<br>
&SYSTEM<br>
ibrav = 0,<br>
celldm(1) = 12.42108529,<br>
nat = 31,<br>
ntyp = 2,<br>
ecutwfc = 28.0D0,<br>
ecutrho = 280.0D0,<br>
occupations ='smearing',<br>
smearing ='gaussian',<br>
degauss = 0.005,<br>
/<br>
&ELECTRONS<br>
conv_thr = 1.D-8,<br>
mixing_beta = 0.3D0,<br>
/<br>
&IONS<br>
/<br>
ATOMIC_SPECIES<br>
Zn 65.39 Zn.pbe-van_ak.UPF<br>
O 15.99 O.pbe-van_ak.UPF<br>
BEGIN_POSITIONS<br>
FIRST_IMAGE<br>
ATOMIC_POSITIONS {angstrom }<br>
Zn 0.000000000 0.000000000 -0.000901300<br>
O 0.000000000 0.000000000 1.982166429<br>
Zn 1.618166296 0.934248744 2.660882286<br>
O 1.587537112 0.916564976 4.668341083<br>
Zn 0.000000000 0.000000000 5.549324230<br>
Zn 1.510731530 0.872221253 7.785147076<br>
O 1.614761747 0.932283127 9.789420866<br>
Zn -1.647149135 2.813900718 -0.034865746<br>
O -1.647131851 2.813910697 1.979064959<br>
Zn 0.000000002 3.764882713 2.578931174<br>
O 0.000000002 3.764882713 4.586148646<br>
Zn -1.624551499 2.826947470 5.242777187<br>
O -1.641528837 2.817145598 7.246106096<br>
Zn 0.000000002 3.764882713 7.873821255<br>
O 0.000000002 3.764882713 9.870733921<br>
Zn 3.260484073 0.019522635 -0.034865746<br>
O 3.260484073 0.019502678 1.979064959<br>
Zn 4.902801854 0.934248744 2.660882286<br>
O 4.933431038 0.916564976 4.668341083<br>
Zn 3.260484073 -0.006570867 5.242777187<br>
O 3.260484073 0.013032875 7.246106096<br>
Zn 5.010236620 0.872221253 7.785147076<br>
O 4.906206403 0.932283127 9.789420866<br>
Zn 1.647149135 2.813900718 -0.034865746<br>
O 1.647131851 2.813910697 1.979064959<br>
Zn 3.260484075 3.778826580 2.660882286<br>
O 3.260484075 3.814194115 4.668341083<br>
Zn 1.624551499 2.826947470 5.242777187<br>
O 1.641528837 2.817145598 7.246106096<br>
Zn 3.260484075 3.902881561 7.785147076<br>
O 3.260484075 3.782757814 9.789420866<br>
LAST_IMAGE<br>
ATOMIC_POSITIONS {angstrom }<br>
Zn 0.119469042 0.068975484 -0.085296951<br>
O 0.015207179 0.008779869 1.918954244<br>
Zn 1.630247715 0.941223955 2.620686267<br>
O 1.630247715 0.941223955 4.604032865<br>
Zn 0.012421523 0.007171570 5.284174983<br>
O 0.042886882 0.024760753 7.291900841<br>
Zn 1.630247715 0.941223955 8.172918735<br>
Zn -1.630247713 2.823671869 0.005029795<br>
O -1.630247713 2.823671869 2.001908162<br>
Zn 0.017145427 3.774794739 2.588903716<br>
O 0.016953247 3.774683784 4.602875645<br>
Zn -1.630247713 2.823671869 5.202337904<br>
O -1.630247713 2.823671869 7.209073955<br>
Zn -0.005796021 3.761549488 7.866297372<br>
O 0.010971356 3.771230138 9.869611927<br>
Zn 3.141026385 0.068975484 -0.085296951<br>
O 3.245288248 0.008779869 1.918954244<br>
Zn 4.890743142 0.921426124 2.588903716<br>
O 4.890743142 0.921648034 4.602875645<br>
Zn 3.248073903 0.007171570 5.284174983<br>
O 3.217608545 0.024760753 7.291900841<br>
Zn 4.890743142 0.947916625 7.866297372<br>
O 4.890743142 0.928555326 9.869611927<br>
Zn 1.630247713 2.685720902 -0.085296951<br>
O 1.630247713 2.806112131 1.918954244<br>
Zn 3.243350004 3.774794739 2.588903716<br>
O 3.243542184 3.774683784 4.602875645<br>
Zn 1.630247713 2.809328729 5.284174983<br>
O 1.630247713 2.774150362 7.291900841<br>
Zn 3.266291452 3.761549488 7.866297372<br>
O 3.249524075 3.771230138 9.869611927<br>
END_POSITIONS<br>
K_POINTS { gamma }<br>
CELL_PARAMETERS (alat)<br>
0.990204093 0.000000000 0.000000000<br>
-0.495102046 0.857541899 0.000000000<br>
0.000000000 0.000000000 1.593439130<br>
END_ENGINE_INPUT<br>
END<br></font>
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