| Abstract: | A direct simulation Monte Carlo (DSMC) method was modified in order to analyze the evaporation process in atomic vapor laser isotope separation (AVLIS), whereby energy transfer between discrete energy levels of metastable states and continuous energy level of translation took place. The atomic excitation temperatures of gadolinium atom were calculated for the model in five low-lying states. Calculation results were compared with those of the experiments obtained by laser absorption spectroscopy. Two types of DSMC simulations which were different in inelastic collision procedures were carried out. It was concluded that the energy transfer was forbidden unless the total energy of the colliding atoms exceeded a threshold value. It was also found that the DSMC method is suitable for treating deexcitation of metastable states accompanied by rapid expansion in the AVLIS evaporation process. |
