The reaction and reaction rate constant of BVOC oxidation to SVMT1-6 by oxidation of BVOC in CMAQv5.3.2 have not been found.
Please see the table immediately below the figure at CMAQ/aero7_overview.md at 5.3.2 · USEPA/CMAQ · GitHub
Details on the monoterpene SOA MT1-6 species can be found at the reference Xu et al. 2018 ACP. Details are available in the SI of that paper. See also the mechanism file for the code (mech*.def).