Simulation of dissociation effect at high temperature and high pressure by REMC method

Abstract

Considering the zero-point vibration energy of fluid H₂, the dissociation process of fluid H₂ at different temperatures and densities under 10000 K was studied by using the REMC (reaction ensemble Monte Carlo) method based on classical theory, and the results of different methods were compared and analyzed. The variation of the dissociation degree with temperature predicted by the REMC method is similar to that of the DM method, and the value of the dissociation degree is closest to that of the TB-II method. The dissociation degree of fluid H₂ is less than 38% at 10000 K. According to this REMC method, the fluid D₂ begins to dissociate when the shock pressure reaches 20 GPa. When the shock pressure is 50 GPa, the dissociation degree is 23.88%; At 100 GPa, the dissociation degree is 61.30%. The calculated dissociation value of fluid D₂ is lower than that of the QMD method under high temperature and high pressure, while it is in good agreement with the experimental results derived from light gas gun under low temperature and low pressure.