Different Number of Molecules in Simulation

I am reading some paper on Thermal decomposition of polymers/hydrocarbons, in those paper they have calculated the count of different number of molecules formed at higher temperature, for example if we add CH4 to a box containing O2 molecules at high temperature, after some time species such as CH3, COOH, CO2 will be formed, how can we keep count of each molecules formed in Lammps. Any help to proceed in right direction.

Thanks

I am reading some paper on Thermal decomposition of
polymers/hydrocarbons, in those paper they have calculated the count of
different number of molecules formed at higher temperature, for example
if we add CH4 to a box containing O2 molecules at high temperature,
after some time species such as CH3, COOH, CO2 will be formed, how can
we keep count of each molecules formed in Lammps. Any help to proceed in
right direction.

studying this kind of reactions in lammps is only possible
using the reax force field, which in turn has no explicit concept
of molecules. you will have to post process the bonding information
and make an informed choice about what you are considering
a "proper" bond.

axel.