From NWChem
Viewed 1856 times, With a total of 1 Posts

Just Got Here
Threads 1
Posts 1


1:57:32 PM PST  Wed, Dec 10th 2014 

Hello,
I have some convergence problem with my system. First i have tried to use atomic energies as a initial guess:
Sum of atomic energies: 12168.89600910
However, in the first step of the self consistent field iteration the calculated energy is much lower (around 3000 Hartree) than the sum of atomic energies.
convergence iter energy DeltaE RMSDens Diiserr time
      
COSMO solvation phase
d=95,ls=0.0,diis 1 9070.3026315120 3.81D+04 2.12D+00 3.75D+03 2432.4
1.36D+00 3.75D+03
...
Grid integrated density: 881.000491141720
Requested integration accuracy: 0.10E07
d=95,ls=0.5,diis 20 8896.2436450218 2.10D+01 1.03D+00 7.86D+03 39285.7
1.08D+00 7.85D+03
Furthermore, the energy does not converge. Even with a very high damping factor the energy value become lower.
charge 1
geometry units angstrom noautosym noautoz
...
end
basis spherical
C library Def2SVP
H library Def2SVP
N library Def2SVP
O library Def2SVP
S library Def2SVP
Fe library Def2SVP
end
cosmo
dielec 4.0
do_gasphase false
end
dft
xc b3lyp
odft
mult 2
noio
direct
grid xfine
iterations 400
mulliken
vectors input atomic output NoCDFT.mos
convergence damp 95
convergence ncydp 400
end
Any idea how it can be fixed?

Edited On 2:01:14 PM PST  Wed, Dec 10th 2014 by McBudaTea




Huub Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop


Forum Regular
Threads 1
Posts 185


4:32:36 PM PST  Sat, Feb 14th 2015 

You have set
do_gasphase false
Hence you are doing a COSMO calculation where you are embedding you system in a field of point charges to represent the solvent. But now you are calculating the embedding charges from a unconverged charge density. At that point anything can happen.
I would recommend running the gas phase calculation first. That might help a lot. Suppressing the gas phase calculation is a good idea for example in geometry optimizations where you have a sensible wavefunction from the previous point. For a single point calculation it is not recommended.



AWC's:
2.5.10 MediaWiki  Stand Alone Forum Extension
Forum theme style by: AWC