Effects ofAdesorption on the first-order transition in theA-B2reaction model

The A-${\mathit{B}}_2$ surface-reaction model [R. M. Ziff, E. Gulari, and Y. Barshad, Phys. Rev. Lett. 56, 2553 (1986)] is studied including spontaneous desorption of CO from the catalyst surface. It is found that when the spontaneous desorption probability P is above a critical value ${\mathit{P}}_{\mathit{c}}$>0.039, the system no longer exhibits a first-order kinetic phase transition. The interface between coexisting phases is found to be nonfractal for P below ${\mathit{P}}_{\mathit{c}}$, but it becomes fractal with dimension D=1.46±0.05 when P=${\mathit{P}}_{\mathit{c}}$. The critical behavior of the model is qualitatively described by Dickman’s one-site mean-field approximation.