Simulations of vibrational relaxation in dense molecular fluids. I. Methods

In the understanding of high-temperature and high-pressure chemistry in explosives, the first step is the study of the transfer of energy from translational degrees of freedom into internal vibrations of the molecules. We present new methods using nonequilibrium molecular dynamics (NEMD) for measuring vibrational relaxation in a diatomic fluid, where we expect a classical treatment of many-body collisions to be relevant because of the high densities (2 to 3 times compressed compared to the normal fluid) and high temperatures (2000–4000 K) involved behind detonation waves. NEMD techniques are discussed, including their limitations, and qualitative results presented.