No unimolecular isomers left to explore

[wang-zj2023]

Context

I'm currently using the Developer Install version of RMG on Ubuntu to generate models for my research, but I'm frequently encountering the following error:

Error: Trying to step from time 0.0 to 1e-12 resulted in a solver (DASPK) error: nans in moles
Resurrecting Model...
At time 1.0000e-15 s, species He(14) at rate ratio 0.0 was added to model core in model resurrection process
At time 1.0000e-15 s, PDepNetwork #1 at network leak rate nan was sent for exploring during model resurrection process
conditions choosen for reactor 1 were: T = 1227.0757087411973 K, CO2 = 0.03600739897708978, CH4 = 0.024, C2H6 = 0.003, C3H8 = 0.003, O2 = 0.01608, Ar = 0.9179126010229102,
Traceback (most recent call last):
File "/home/wang/miniconda3/envs/rmg_env/lib/python3.7/site-packages/julia/pseudo_python_cli.py", line 308, in main
python(**vars(ns))
File "/home/wang/miniconda3/envs/rmg_env/lib/python3.7/site-packages/julia/pseudo_python_cli.py", line 59, in python
scope = runpy.run_path(script, run_name="main")
File "/home/wang/miniconda3/envs/rmg_env/lib/python3.7/runpy.py", line 263, in run_path
pkg_name=pkg_name, script_name=fname)
File "/home/wang/miniconda3/envs/rmg_env/lib/python3.7/runpy.py", line 96, in _run_module_code
mod_name, mod_spec, pkg_name, script_name)
File "/home/wang/miniconda3/envs/rmg_env/lib/python3.7/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "rmg.py", line 118, in
main()
File "rmg.py", line 112, in main
rmg.execute(**kwargs)
File "/home/wang/RMG-Py/rmgpy/rmg/main.py", line 1010, in execute
reactor_done = self.reaction_model.add_new_surface_objects(obj, new_surface_species, new_surface_reactions, reaction_system)
File "/home/wang/RMG-Py/rmgpy/rmg/model.py", line 770, in add_new_surface_objects
k.get_maximum_leak_species(reaction_system.T.value_si, reaction_system.P.value_si) for k in obj if isinstance(k, PDepNetwork)
File "/home/wang/RMG-Py/rmgpy/rmg/model.py", line 770, in
k.get_maximum_leak_species(reaction_system.T.value_si, reaction_system.P.value_si) for k in obj if isinstance(k, PDepNetwork)
File "/home/wang/RMG-Py/rmgpy/rmg/pdep.py", line 237, in get_maximum_leak_species
raise NetworkError('No unimolecular isomers left to explore!')
rmgpy.exceptions.NetworkError: No unimolecular isomers left to explore!

Installation Information

Describe your installation method and system information if applicable.

• OS (include version if known): Win11 wsl2-Ubuntu 22.04
• Installation method: source
• RMG version information:
  • RMG-Py: 3.2

[mjohnson541]

This is almost always a consequence of poor thermochemistry for some species (which is causing the solver to fail triggering model resurrection) although it can theoretically result from poor kinetics. I would check your thermochemistry libraries and see if one of them (or possibly even a lack of one) is associated with these failures. RMS (installed with RMG: https://github.com/ReactionMechanismGenerator/ReactionMechanismSimulator.jl) has simulation debug tools that can detect the species/reactions causing the failure automatically, but you have to setup the simulation to use them.