Monte Carlo simulation study of the effects of nonequilibrium chemical reactions during pulsed laser desorption

Abstract

Monte Carlo simulation is used to study the role of chemical reactions in the gas flow of particles laser desorbed from the target into a vacuum. The influence of recombination and dissociation processes on the properties of the gas flow is considered. It was found that chemical reactions have a significant effect on the composition of the desorption jet and on the angular and mean energy distributions of the desorbed particles. The study of these phenomena is of a particular interest for the understanding of the process of thin film deposition by pulsed laser ablation.

Angular and energy distribution of Sn ion debris ejected from a laser-produced plasma source, for laser power densities in the range suitable for extreme ultraviolet lithography

“…49 Simulations of the effect of particle collisions within this Knudsen layer have demonstrated preferential emission of higher energy particles close to target normal as the result of elastic collisions. 50,[52][53][54] The angular emission cone of these high-energy particles was observed to narrow with increased number of collisions/increased desorption from the target surface. 52 Studies by Urbassek and Sibold 51 have shown that the collisional frequency varies as q 4 , where q is the ion charge, relating the ion energy with charge.…”

Laser–Matter Interaction in LIBS Experiments

“…Moreover, when the velocities of the ejected material deviate sensibly from a Maxwellian distribution, dynamical models are ruled out due to the presence of steep density gradients. One solution is to turn to a microscopic description via Monte Carlo simulations [61] or a combination of both [57,61,62]. Monte Carlo methods, however, become numerically expensive above pressures of 10 Pa.…”

Mechanisms of Nanoparticle Formation by Laser Ablation

“…In the model, two different numerical methods are used (i) molecular dynamics for target material disintegration and ejection of a mixture of clusters and monomers (14); and (ii) direct simulation Monte Carlo for the calculation of large-scale three-dimensional plume evolution (Itina et al, 1997). Here, as in the previous MD calculations (Zhigilei et al, 1998;Zeifman et al, 2002), the breathing sphere model is adopted to model laser pulse absorption and relaxation processes in the MD part.…”