GreenGroup/RMG-Java — Issue #237: Negative steady-state concentration error from fame
Author: gmagoon
Created: 2011-12-12 16:00:14+00:00
State: open

One of my jobs recently crashed due to a failure of fame. Running the input file gives the following at stdout:

ERROR: One or more rate coefficients not properly estimated. See fame.log for details.
The message returned was:
A negative steady-state concentration was encountered.

The input and fame.log files are at:
https://github.com/downloads/GreenGroup/RMG-Java/19b_input.txt
https://github.com/downloads/GreenGroup/RMG-Java/19b_output.txt

At the suggestion of @jwallen, I tried playing with the lower temperature bound. We found that raising the lower bound and the lowest Chebyshev temperatures by 200 K (so the lower bound was 500 K) does not produce this error. I also found that REDUCING the lower bound and the lowest Chebyshev temperature by 20 K also seems to complete without this error. Raising these two temperatures by just 3 K also completes without error. So, it seems that, for whatever reason, there is a narrow temperature range where this error is obtained.