  The equation of state of the triclinic compound
1,3,5-triamino-2,4,6-trinitrobenzene (TATB) as well as its second-order
isothermal elastic tensor were computed through classical molecular dynamics
simulations under various temperature and pressure conditions. Hydrostatic
pressures similar to previous diamond anvil cell experiments were imposed
within the range [0, 66] GPa and temperatures chosen between 100 and 900 K in
conjunction with the most recent version of an all-atom fully-flexible molecule
force field. The isothermal elastic constants were computed using the
generalized Hooke's law by fitting Cauchy stress vs. linear strain curves.
Along isobaric pathways, TATB single crystal stiffness is found to undergo
linear softening, less pronounced at high pressure, while maintaining its
elastic anisotropy. On the other hand, along an isothermal pathways, a
non-linear increase is observed in the elastic constants with a significant
decrease in anisotropy. Towards a precise mesoscopic modeling of TATB single
crystal mechanical behavior, we provide "ready to plug-in" analytical
formulations of the P,V,T equation of state and pressure-temperature dependent
non-linear elasticity.
