N-R didn't converge after 999 its.

[Frank Bok]

Hello,

 

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,

Frank

[Brian Farrell]

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.

 

Regards,

 

Brian Farrell

Aqueous Solutions LLC

[Frank Bok]

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,

Frank

[Brian Farrell]

Glad to help, Frank.

 

Best,

Brian