From NWChem
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Just Got Here
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| 11:34:44 AM PST - Wed, Jan 9th 2013 |
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Dear All,
I have been trying to calculate the band structure of tin for a while without success so far. I use version 6.1 on Linux, but I get the same error with 6.0 in serial and in parallel mode as well. The input is the following:
start Tin
title "White Tin Band Structure"
permanent_dir ./perm
scratch_dir ./scratch
geometry center noautosym noautoz print
system crystal
lat_a 5.80
lat_b 5.80
lat_c 3.15
alpha 90.0
beta 90.0
gamma 90.0
end
Sn 0.0 0.0 0.0
Sn 0.5 0.5 0.5
Sn 0.5 0.0 0.25
Sn 1.0 0.5 0.75
end
nwpw
ewald_rcut 3.0
ewald_ncut 8
monkhorst-pack 3 3 3
end
task band energy
nwpw
virtual 16
brillouin_zone
zone_name bctpath
path bct gamma x m gamma
end
zone_structure_name bctpath
end
task band structure
I get the band energy, so the first task seems to complete without a problem, but whatever I try, I cannot get the second part to produce anything meaningful. Instead, I get:
Total BAND energy : -0.1905413631E+02
Self-Consistent Potential Generated
output psi filename:./perm/Tin.movecs
band structure calculation
== Optimizing Brillouin Zone Point: 1 ==
Brillioun Zone Points do not match!
NB = 14 not equal 1
pseudopotential is not correctly formatted---bad brillioun zone:
Sn.cpp
Generated formatted_filename: ./perm/Sn.cpp
Brillioun Zone Vectors do not match!
pseudopotential is not correctly formatted---bad brillioun zone:
Sn.cpp
Generated formatted_filename: ./perm/Sn.cpp
Brillioun Zone Vectors do not match!
where the last four lines keep repeating in the output file until I kill the job. If I leave it, it produces thousands of the same error message. The same task is running fine with diamond which is an example in the documentation, but I could not figure out what non-trivial options I should change for white tin. BTW, the same error message appears in the case of diamond too, but just once for each Brillouin zone points, and then the calculation is going on until it finishes successfully. Does anyone have any idea how to interpret these error messages and what could be the solution or workaround? Tin is special for some reason, or is this a more general problem?
Also, there are a number of options, which I am quite uncertain about, because the documentation hardly mentions them. A few of these are:
set nwpw:kbpp_ray .true.
set nwpw:kbpp_filter .true.
# turn on pseudopotential filtering. ??? When is it relevant? What is it exactly doing?
smear fermi
scf anderson outer_iterations 0 kerker 2.0
# The documentation only says that these are the options "recommended for running fractional occupation" Some more reference?
np_dimensions -1 -1 4
# Why 4? Sometimes it is 6. Any description anywhere? In this forum, I could only find that "the third dimension refers to the distribution over k-space vectors (parallelization similar to VASP)." Apart from repeating this answer, I couldn't explain to anyone what is this number after all.
I really appreciate the lots of features that NWChem offers, but if they are not documented, they just appear in some examples, it is not easy to figure out whether you need them or not, with the same settings, or not, unless you need to do the exact same calculation that is in the the example. Apart from the documentation, so far I couldn't find any other source than this forum and Google, and I have lots of questions. Initially I was hoping for a somewhat more efficient way of setting up an input with optimal arguments, where you actually know what you are doing. Otherwise I like the software, but with all due respect, the documentation needs to be updated. I am reluctant to publish its output if I don't even fully understand the input. Until then any suggestions and hints regarding the above options are welcome.
Many thanks in advance!!!
Csaba
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Edited On 10:46:44 AM PST - Thu, Jan 10th 2013 by Pecsabi
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