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N-R didn't converge after 999 its.

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I've created a minimal database with data for Na+, Cl- and some Europium(III) hydrolysis species. GWB (9.0.3) gives no errors when loading this database (Europium_test.dat).

With this database I want to do a Eu speciation calculation as a function of pH (Eu-Hydrolysis.rea). But GWB allways stops with the message:


Solving for initial system.


Loaded: 9 aqueous species,

1 minerals,

0 gases,

0 surface species,

5 elements,

0 oxides.


Reading conductivity data from: C:\Users\fb5950\GWB\Gtdata\conductivity.dat

N-R didn't converge after 999 its., maximum residual = 1, Xi = 0.0000

Largest residual(s):

Resid Resid/Totmol Cbasis


Cl- 1.007e+200 1 3.406e-109

Eu+++ 5.109e+200 1 1.467e-108

Na+ 1.007e+200 1 3.405e-109



Could you help me with this, please!


Thanks and best regards,


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Hi Frank,


After messing around with your dataset, I found I could get your React script to run once I set a value for the c H2O-1 coefficient at 25 C. This is the first term used in the water activity calculation (see the Geochemical and Biogeochemical Reaction Modeling text, equation 8.8). I just took the value of 1.45397 from thermo.dat.




Brian Farrell

Aqueous Solutions LLC

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Hi Brian,


thank you for your quick response and help. It seems our parameter file generator for the Debye-Huckel model is not working perfectly, which I had previously overlooked!

Thanks again and best regards,


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