I am a beginner with Reactive MD and am working on the thermal stability of polymer compounds composed of polyester and organic additive. The idea is to study the reaction pathways and evolution of reactive species during heating using ReaxFF.
I employ the force field parameters from https://doi.org/10.1021/acs.jpca.7b05257 for PHCO, and I want to validate if it is suitable for my system. The plan is to do a test for a small system, i.e. a polymer chain with an additive molecule. First, I do non-reactive MD with NVT ensemble equilibrated at 300K. Then, I plan to conduct reactive MD simulations heating from 300K to 1000K/1500K/2000K. To validate the parameters, I will compare the cohesive energies from ReaxFF and from DFT using CASTEP, like plotting E/atom against the number of atoms. I am not sure if it is enough for validation. Could anyone help me out?
Besides, I am wondering how can I get the evolution information of species. Should I dump molecule ID?
FYI, my input script has been attached.
#package gpu 4 gpuID 0 3 #units real #atom_style charge #read_data data.mix_0.5 #pair_style reax/c NULL #pair_coeff * * ffield.reax.PHCO H C O H P #newton on #fix 1 all qeq/reax 1 0.0 10.0 1.0e-6 reax/c #minimize 1.0e-4 1.0e-6 100 10000 #write_restart restart.minimizer #clear package gpu 4 gpuID 0 3 units real atom_style charge read_restart restart.minimizer pair_style reax/c NULL pair_coeff * * ffield.reax.PHCO H C O H P newton on neighbor 2 bin neigh_modify every 10 delay 0 check no restart 1000000 restart reset_timestep 0 fix 1 all nve #fix 1 all nvt temp 300.0 1000.0 100.0 #fix 1 all npt temp 1000.0 1000.0 100.0 iso 1.0 1.0 1000.0 fix 2 all qeq/reax 1 0.0 10.0 1.0e-6 reax/c thermo 10 thermo_style custom step temp cpu pe etotal evdwl ecoul vol density timestep 0.1 dump 1 all atom 10000 dump_mix-0.5pct.lammpstrj run 10000000 undump 1
Thank you very much for reading my questions!