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Newton-Raphson did not converge after 999 iterations

Frank Bok

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I have prepared a database (attached) and both TEdit and React are loading the file without any warning. But even the simplest calculations fail and give an error message like this:


Solving for initial system.

 Loaded:    5 aqueous species,
            0 minerals,
            0 gases,
            0 surface species,
            4 elements,
            0 oxides.

Newton-Raphson did not converge after 999 iterations, maximum residual =           1, Xi = 0.0000
Largest residual(s):
                       Resid     Resid/Totmol   Cbasis
 Cl-                1.007e+200            1   3.406e-109
 Na+                2.007e+200            1   6.813e-109

Is there a way to locate the error to make it work?

Thank you in advance and best regards,



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Hi Frank,

The biggest problem is that you’re missing values for Bdot and the water activity coefficient terms in the Tables section of your thermo dataset. You’ll probably also want to set real values  for the ion size parameter for the basis and aqueous species, since 500 is currently being used.

For more information, please see the Thermo Datasets chapter of the GWB Reference Manual.


Brian Farrell
Aqueous Solutions LLC

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Hi Brian,

thank you for the information. Acutally I wanted to use the activity model "phreeqc" so this is one of the reasons I got in this trouble. I should more often remember to "RTFM"... ;-)

Thank you and best wishes!


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