A+B2表面催化反应相变及自振荡的蒙特卡罗模拟

用MonteCarlo法研究了脱附和E－R机理对不可逆催化氧化反应A＋1／2B2→AB的相交和自振荡的影响、结果表明，（1）催化剂表面A的脱附使ZGB模型中的一级相变点消失，但对二级相交点的影响很小；当有E－R机理参与时，二级相交点消失，且E－R过程的几率对一级相交点的影响较大；当A的脱附和E－R过程同时起作用时，上述反应不存在相交（2）在ZGB模型中的二级相变点附近，反应速率随时间的变化具有明显的振荡现象，在其它位置主要表现为噪音。引入A的脱附后在二级相交点附近明显的自振荡现象依然存在；当E-R过程起作用时，随着二级相交点的消失，明显的振荡现象亦随之消失．（3）A的脱附和E－R过程对上述反应相变的影响与A的表面扩散对相变的影响有着本质的区别，因为后者只能改变相变点的位置而不能改变相变点的存在状况．

Monte Carlo Simulation of the Phase Transition and Self-oscillation in A B_2 Surface Catalytic Reaction

The influences of A desorption and E-R mechanism on the phase transitions and self-oscillations in the irreversible catalytic oxidation reaction of A + 1/2 B2 → AB were studied in detail by Monte Carlo simulation. It was found that (1) the first order phase point observed in ZGB model disappears when A desorption is considered; (2) the second order phase transition point observed in ZGB model disappears when E-R mechanism concerned with A(g) and adsorbed B atom is considered; (3) there is no phase transitions in the reaction when both A desorption and E-R mechanism are considered; (4) there is obvious rate oscillation in the neighbourhood of the second order phase transition point of ZGB model, but only noise at other positions of A partial pressure, so there are no oscillations when E-R mechanism is considered or both E-R mechanism and A desorption are considered in our extended model.