antiferromagnetic coupling


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Hi,

I am trying to get previously reported (by other codes) antiferromagnetic state for the icosahedral Fe_13 cluster with nwchem, where the centrel atom couples antiferromagnetically with the surface atoms. However, I am failing consistently. The problem is that energy is not converging with fragment molecular orbitals.

Here is my input file and I will appreciate any advice.


echo

start molecule
memory total 4 GB

title "Title"
charge 0

geometry ico units angstroms print xyz noautosym
Fe     -0.00100206     0.00133401     0.00045323
Fe 1.82985810 1.35666429 0.73074913
Fe -1.83913623 -0.42791020 1.43351191
Fe -0.47052055 1.85235404 1.50989083
Fe 0.28819443 2.19767280 -0.98554175
Fe 1.98106379 -1.17799630 0.66511492
Fe 0.48666317 -0.20250684 2.37034195
Fe -1.95007828 1.33933627 -0.39616680
Fe -0.52359503 0.30245996 -2.34834578
Fe 1.82103339 0.10691604 -1.52506211
Fe 0.48038006 -1.92315065 -1.40057508
Fe -0.25222278 -2.23551426 0.90949934
Fe -1.85063801 -1.18965917 -0.96386978
end
geometry cen units angstroms print xyz noautosym
Fe     -0.00100206     0.00133401     0.00045323
end
geometry surface units angstroms print xyz noautosym
Fe      1.82985810     1.35666429     0.73074913
Fe -1.83913623 -0.42791020 1.43351191
Fe -0.47052055 1.85235404 1.50989083
Fe 0.28819443 2.19767280 -0.98554175
Fe 1.98106379 -1.17799630 0.66511492
Fe 0.48666317 -0.20250684 2.37034195
Fe -1.95007828 1.33933627 -0.39616680
Fe -0.52359503 0.30245996 -2.34834578
Fe 1.82103339 0.10691604 -1.52506211
Fe 0.48038006 -1.92315065 -1.40057508
Fe -0.25222278 -2.23551426 0.90949934
Fe -1.85063801 -1.18965917 -0.96386978
end

basis spherical
  * library stuttgart_rsc_1997_ecp
end

ecp
  * library stuttgart_rsc_1997_ecp
end

set geometry cen
dft
xc becke88 lyp
mult -5
vectors input atomic output center.movecs
iterations 555
convergence energy 1e-5
end
task dft

set geometry surface
dft
direct
xc becke88 lyp
mult 41
vectors input atomic output surface.movecs
iterations 777
convergence energy 1e-5
end
task dft

set geometry ico
dft
direct
xc becke88 lyp
mult 37
vectors input fragment center.movecs surface.movecs output ico.movecs
iterations 777
convergence energy 1e-5
end
task dft

dft
direct
xc becke88 lyp
mult 37
iterations 777
vectors input ico.movecs output ico-dft.movecs
convergence energy 1e-5
end

driver
maxiter 333
end

task dft optimize