Potential of mean force calculations using ab initio tight-binding molecular dynamics: Application to N-NO2 bond dissociation in DMNA and HMX

We present results on the N-NO2 bond dissociation in gas-phase DMNA and HMX. The results obtained in our calculations are in good agreement with other methodologies, which demonstrates that the umbrella sampling model implemented in FIREBALL is able to correctly predict the free energies changing along the reaction potential surface.