Investigation of the first-order phase transition in theA-B2reaction model using a constant-coverage kinetic ensemble

The first-order kinetic transition in the A-${\mathit{B}}_2$ (or Ziff-Gulari-Barshad) surface-reaction model [Phys. Rev. Lett. 56, 2553 (1986)] is investigated using a simulation algorithm (or ensemble) in which the coverage of A is held fixed, while the rate y of A adsorption is allowed to vary. This ensemble allows the metastability loop and spinodal point of the phase transition to be carefully examined. The metastable behavior is found to be in qualitative agreement with the predictions of mean-field theory made by Dickman [Phys. Rev. A 34, 4246 (1986)]. Furthermore, the transition point is precisely determined to be ${\mathit{y}}_2$=0.525 60±0.000 01. The metastable behavior near the spinodal point is also investigated using the standard constant-rate algorithm.