Study of the one-dimensional off-lattice hot monomer reaction model

Hot monomers are particles having a transient mobility (a ballistic flight) prior to being definitely absorbed on a surface. After arriving at a surfa ce, the excess energy coming from the kinetic energy in the gas phase is di ssipated through degrees of freedom parallel to the surface plane. In this paper we study the hot monomer-monomer adsorption-reaction process on a con tinuum (off-lattice) one-dimensional space by means of Monte Carlo simulati on. The system exhibits a second-order irreversible phase transition betwee n reactive and saturated (absorbing) phases which belong to the directed pe rcolation (DP) universality class. This result is interpreted by means of a coarse-grained Langevin description which allows us to extend the DP conje cture to transitions occurring in continuous media.