Invalid k(E) at high T for BM rate rule estimate

[davidfarinajr]

@ChrisBNEU and I are testing my halogens pdep PR with the 1,3-hexadiene pyrolysis example (without mopac).

RMG is crashing on main branch with this error

Warning: For path reaction [CH2]C(C=CCC)C([CH2])C=CCC(50) <=> [CH2]C=CC(CC)C([CH2])C=CCC(47):
Warning:     Expected kf(1896.74 K) = 2.39965e+11
Warning:       Actual kf(1896.74 K) = 7.72355e+10
Warning:     Expected Keq(1896.74 K) = 10.7667
Warning:       Actual Keq(1896.74 K) = 0
Error: Invalid k(E) values computed for path reaction "[CH2]C(C=CCC)C([CH2])C=CCC(50) <=> [CH2]C=CC(CC)C([CH2])C=CCC(47)".
Error: Increasing number of grains did not decrease error enough (Current badness: 0.5, previous 0.5). Something must be wrong with network PDepNetwork #13

website kinetics

Not sure if this is due to a bad microcanonical rate due to poor density of state estimates from group freqs, or a poor high pressure rate at 1900 K (or both). Since the high P kinetics are fit to 300 - 1500 K range, and the T exponent is ~22, the rate may be too fast at T > 1500 K

[kspieks]

Thanks @mjohnson541 for notifying me of this issue. I recently created the 1,3 sigmatropic rearrangement reaction family (PR 532 on RMG-database) that is involved in this issue and wanted to share an update.

Based on the picture above, the problem is with this node in the rate tree: Root_N-1R!H-inRing. Previously, the estimate at this node was rather interesting... (link)

label = "Root_N-1R!H-inRing",
ArrheniusBM(A=(3.50759e-62,'s^-1'), n=22.1275, w0=(750402,'J/mol'), E0=(-20429.3,'J/mol') ...
Total Standard Deviation in ln(k): 13.494121433083981"""),

However, I recently made a new PR on RMG-database (PR 550) that adds a thermo library for the species involved in the training reactions I had added that were used to fit this tree. On the new PR, the rate estimate for this specific node looks more reasonable and the standard deviation decreased (link)

label = "Root_N-1R!H-inRing",
kinetics = ArrheniusBM(A=(1.69526e+13,'s^-1'), n=-0.0541346, w0=(705700,'J/mol'), ...
Total Standard Deviation in ln(k): 8.759382282596956"""),

I do not know how relevant this change in the rate estimate is vs. other potential issues, perhaps RMG struggling with biradicals? None of the training reactions I had added involve radicals (let alone biradicals) so perhaps the thermo I added for the stable species will not matter for this specific reaction. Anyways, just wanted to share this info

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