Simulations of desorption from amorphous films

The structure of amorphous films formed at low temperatures is characterized by an abundance of unconnected bonds and/or topological disorder associated with variation in the number of particles forming elementary cells. Desorption from such films, occurring at higher temperature, may be complicated by film crystallization resulting from diffusion of particles. We present the first Monte Carlo simulations explicitly treating the interplay of all these processes. Specifically, we analyze desorption from thin porous two-dimensional lattice films (up to 100 monolayers) generated by using the ballistic-deposition rules. Employing various schemes of diffusion of particles in the film, we demonstrate that for the model under consideration the desorption rate is initially high, but then it rapidly drops and further on becomes nearly constant, i.e. the apparent order of the desorption kinetics is close to zero. Illustrating potential applications of the results obtained, we briefly discuss water desorption from amorphous ice films.