An expansion of a bicomponent laser plume into a dilute ambient gas is simulated using a combined direct simulation-random trajectory Monte Carlo method. The stoichiometry of thin films deposited from laser-desorbed material on a flat substrate is examined. In the case of energy-dependent particle adsorption probability, the dependencies of deposition rate on the background pressure are shown to be nonmonotonic with maximums at low gas pressure. In addition, an increase in the ratio of light to heavy species was obtained at low pressure. We demonstrate that these results can be attributed to the interplay between the effects of collisions with the background gas on the fluxes of particles arriving at the substrate and on the adsorption probability of the species. The calculation results are consistent with recent experiments. The study is of interest for the optimization of the experimental conditions during pulsed laser deposition of multicomponent materials