Study On Kinetic Phase Transitions Of M-D And D-D Model On Catalytic Surfaces

In this thesis，we study the kinetic phase transitions of M-D model and D-D modelon catalytic surfaces by using the mean-field equations with the CA time evolutionmethod. The main results are as follows:We study the kinetic phase transition of the A+（1/2）B₂â†'AB（M-D type）surfacecatalytic reaction by means of the mean-field equations with the CA time evolutionmethod. When we ignore the Eley—Rideal （E—R） process and only consider theLangmui—Hinshelwood （L—H） process, two phases are found in theA+（1/2）B₂â†'AB（M-D） type surface catalytic reaction system. They are the Apoisoning phase, the B poisoning phase. When we consider both the Eley—Rideal（E—R） process and the Langmui—Hinshelwood （L—H） process, three phases arefound in the A+（1/2）B₂â†'AB（M-D） type surface catalytic reaction system. They arethe A and Bpoisoning phase and the reaction phase.The results comply with the oneswhich are achieved by simulation method well. The results illustrate the effectivenessof the mean-field method to solve the problem of phase transition.We study the kinetic phase transition of the D-D type surface catalytic reactionwhich has the intermediate product and only a reactant desorption is considered bymeans of the mean-field equations with the CA time evolution method. When weignore the desorption reaction of the reactant, most of the reaction is in poisoningphase. That is a majority of A poisoning phase or B poisoning phase and a minority ofreaction phase. Instead, the desorption reaction of a reactant makes more empty of thecell lattice, which is beneficial to the adsorption of substance and the generation ofreaction phase. We draw a conclusion: the greater degree desorption of the reactant is,the more obvious this phenomenon is. The poisoning phases all disappear and thereaction phase is only left when the desorption rate is p1.We study the dynamics phase transition of D-D type surface catalytic reactionwhich has intermediate product and the lattice catalytic surface with a defect （inertialpoint） is considered by means of the mean-field equations with the CA time evolutionmethod. The surface defect（inertial point） affects the occurrence of the reaction byimpacting the adsorption of reactants. From the reaction equation, we can obtain thefollowing phenomena. When the defect （inertial point） proportion is smaller thand,there exist a part of reaction phases in the reaction, i.e. the A（s）, the B（s） and the AB（s）poisoning phase. When the defect （inertial point） proportion is larger thand, thereaction seepage group is difficult to generate and there are a large proportion ofinertial points in the catalytic surface, i.e. a small number of A（s）, B（s） and AB（s）poisoning phase. There is nearly no response phase until the value ofdis1. So, thecatalytic surface are inertial points.