Dynamic mechanism of the velocity splitting of ablated particles produced by pulsed-laser deposition in an inert gas

Abstract

The transport dynamics of ablated particles produced by pulsed-laser deposition in an inert gas is investigated via the Monte Carlo simulation method. The splitting mechanism of ablated particles is discussed by tracking every ablated particle with their forces, velocities and locations. The force analysis demonstrates that whether the splitting appears or not is decided by the releasing way of the driving force acting on the ablated particles. The "average" drag force, which is related to the mass and radius of the ambient gas, determines the releasing way of the driving force. Our simulated results are approximately in agreement with the previous experimental data.

Monte Carlo Simulation of Laser-Ablated Particle Splitting Dynamic in a Low Pressure Inert Gas

“…Recently, our team also clarified the formation mechanism of the ablatedparticle velocity splitting by this method [11] . The de-tails of the simulation process are shown in the references [11,17] . The force acting on the ablated particles is calculated by a theorem of momentum, F =dp/dt.…”

“…where n is the particle number density, Y is the Enskog Y-factor, and d is the effective collision diameter. In previous works, the mean-free-path, which is only determined by the initial gas density, is fixed during the entire propagation [11,17] . That is, n is considered as a constant.…”

“…Recently, our team simulated the ablated-particle transport dynamic in He or Ar gases at the pressure of 1000 Pa via the Monte Carlo method. The density and velocity distributions are obtained and the formation mechanism of the velocity splitting is also analyzed [11] . The pressure, however, is much higher than that in most of the experiments [12,13] , and the formation mechanism of the two splitting cycles was not distinguished.…”

Pressure ranges of velocity splitting of ablated particles produced by pulsed laser deposition in different inert gases

“…The dynamic mechanism of the velocity splitting has been investigated by us via Monte Carlo simulation. [9] The result shows whether the splitting appears is determined by the releasing way of the driving force acting on the ablated particles. If the velocity range of driving force of the ablated particles obviously decreases with oscillation, the splitting is likely to be observed; otherwise, it cannot be observed.…”

“…The study of transport dynamics of ablated particles in an inert is very important issue in PLD. [4][5][6] During the transport of ablated particles, the velocity splitting, in which the ablated particles split into the distinct slow and fast components, has received much attention, [7][8][9][10] because it affects the size and the density distributions of the nanoparticles. Clarifying the dynamic mechanism and finding the pressure range of the velocity splitting are helpful to realize the controllable preparation of nanoparticles.…”