Revisiting the first-order irreversible phase transition of the Ziff-Gulari-Barshad model

The first-order irreversible phase transition (IPT) characteristic of the Ziff-Gulari-Barshad (ZGB) model is studied by means of extensive numerical simulations. Using the constant-coverage method it is found that hysteresis effects hinder the location of the coexistence point. However, the hysteresis loop is unstable against a negligible small external perturbation, allowing the determination of the coexistence point quite accurately. Also, by means of epidemic studies, an existing controversy on the occurrence of scale invariance in the dynamical behaviour of the system at coexistence is resolved. Our findings reconcile the behaviour of the first-order IPTs of the ZGB model with their reversible counterparts.