CH2* replaced by CH2 for a reaction in JetSurf2.0 mechanism

[PoojaNem]

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Hello Everyone,

I am investigating the kinetic behaviour of SAF surrogates using RMG and used the JetSurf2.0 included in the RMG database to generate a mechanism for n-decane combustion in air.

In one of the reactions of JetSurf2.0 included in the RMG database, CH2* is replaced by CH2 and two reactions have been listed as one with the MultiArrhenius parameter (shown below for reference).

However, in the JetSurf2.0 mechanism online, two separate reactions are available for species CH2 and CH2* (image is provided below for reference). Here is the link to the JetSurf2.0 mechanism I am referring to: https://web.stanford.edu/group/haiwanglab/JetSurF/JetSurF2.0/Mech_JetSurF2.0.txt

To further verify it, I looked into JetSurf1.0 kinetic library in the RMG database. I found it identical to the web version of the mechanism (image attached below for reference) with two reactions for CH2 and CH2*.

It will be helpful if someone can clarify the reason behind this updation from JetSurf1.0 to JetSurf2.0. I have generated the mechanisms in RMG using current JetSurf2.0 in the database and also by modifying the reaction library as per the reaction mechanism available online. Both the mechanisms provide different laminar flame speed results.

Thank you

[PoojaNem]

Here, CH2* or CH2(S) is the singlet methylene and CH2 is the triplet methylene.