Hello,
I'm running into a strange problem when using NWChem 6.6 to calculate single-point energies with the DFT module for a fragment guess. When using the M06-HF, M06-L, or M06 xc functionals, I start to obtain NaN energies after several iterations.
A minimal input file that reproduces the issue:
geometry mn1
symmetry c1
Mn 1.51555 0.49368 -0.79695
Bq -0.16540 1.26690 -0.21663 charge -1 # O phenoxide
Bq 2.80915 -1.21032 -0.74424 charge -1 # N backbone
Bq 3.44038 1.26002 -1.86467 charge -1 # N backbone
Bq 2.37297 1.59393 0.70502 charge -1 # N backbone
Bq 0.20258 -1.29026 -0.05376 charge -1 # O phenoxide
Bq 0.73640 0.02448 -2.38214 charge -1 # O peroxide
end
basis spherical
Mn library "aug-cc-pvdz"
end
set geometry mn1
charge -3
dft
xc m06-hf
direct
odft
mult 5
vectors input atomic output mn1.vec
grid ultrafine
end
title "step 1 : spin-up Mn"
task dft energy
When I submit this input file (NWChem 6.6, LINUX64 platform, 16 MPI tasks), the following occurs:
convergence iter energy DeltaE RMS-Dens Diis-err time
---------------- ----- ----------------- --------- --------- --------- ------
d= 0,ls=0.0,diis 1 -1152.7758220863 -1.11D+03 2.03D-01 3.20D+00 35.2
2.12D-01 1.53D+00
d= 0,ls=0.0,diis 2 -1153.4568255155 -6.81D-01 2.19D-02 1.72D-01 45.9
3.18D-02 1.80D-01
d= 0,ls=0.0,diis 3 -1153.4955096732 -3.87D-02 9.04D-04 9.58D-04 54.1
1.38D-03 1.52D-02
d= 0,ls=0.0 4 NaN NaN 7.40D-04 66.5
1.08D-03
d= 0,ls=0.0 5 NaN NaN 2.31D-04 75.0
4.22D-04
This continues until the maximum number of iterations is reached, at which point NWChem says the calculation failed to converge and exits.
I can only reproduce this problem with the M06 family of functionals - the calculation converges with the B3LYP and M11 functionals.
Any insights would be greatly appreciated!
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