Laser Ablation of Nanoparticles: A Molecular Dynamics Study

2015 ◽  
Vol 1112 ◽  
pp. 120-123 ◽  
Author(s):  
Riser Fahdiran ◽  
Herbert M. Urbassek
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Energy Input ◽  
Laser Energy ◽  
Spherical Shape ◽  
Interatomic Interaction ◽  
Dynamics Simulation ◽  
Lennard Jones ◽  
High Intensity Laser ◽  
Intensity Laser

We study laser ablation of nanoparticles (NPs). The interaction of a high-intensity laser pulse with NPs brings the NP into a highly non-equilibrium state. Depending on the energy input from the laser, it will melt and may fragment and evaporate off atoms and clusters. We employ molecular dynamics simulation to study this interaction since thermodynamic properties can be extracted from output data of this simulation. The interatomic interaction is modeled by a Lennard-Jones (LJ) potential. The intensity of the laser is above the ablation threshold. The NP has been chosen to have a spherical shape with diameter 50 s in LJ units. The laser energy is given to the NP instantaneously at the beginning of the simulation and homogenously to all atoms; it corresponds to an energy input of 5.4 e per atom. The simulation is continued up to a time 200 t in LJ units. Temperature-density phase-space trajectories show that the nanoparticle density and temperature strongly decrease after the irradiation. The pressure in the sphere becomes strongly tensile after irradiation. The ablation proceeds by spallation of the irradiated cluster. We provide an analysis of the fragments produced by the ablation of the spherical NP. Our results are contrasted to the case of laser ablation of a thin-film target.

Molecular Dynamics Simulation of the Ablation Process in Ultrashort Pulsed Laser Machining of Polycrystalline Diamond

2012 ◽  
Vol 500 ◽  
pp. 351-356 ◽  
Author(s):  
Zeng Qiang Li ◽  
Jun Wang ◽  
Qi Wu
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Molecular Dynamics Simulation ◽  
Grain Boundaries ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Polycrystalline Diamond ◽  
Pulsed Laser Ablation ◽  
Dynamics Simulation ◽  
Ultrashort Pulsed Laser

The mechanism of ultrashort pulsed laser ablation of polycrystalline diamond (PCD) is investigated using molecular dynamics simulation. The simulation model provides a detailed atomic-level description of the laser energy deposition to PCD specimens and is verified by an experiment using 300 fs laser irradiation of a PCD sample. It is found that grain boundaries play an important role in the laser ablation. Melting starts from the grain boundaries since the atoms in these regions have higher potential energy and are melted more easily than the perfect diamond. Non-homogeneous melting then takes place at these places, and the inner crystal grains melt more easily in liquid surroundings presented by the melting grain boundaries. Moreover, the interplay of the two processes, photomechanical spallation and evaporation, are found to account for material removal in ultrashort pulsed laser ablation of PCD.

Molecular Dynamics Simulation of Ultrafast Laser Ablation of Fused Silica

2006 ◽  
Author(s):  
Changrui Cheng ◽  
Xianfan Xu ◽  
Yaguo Wang ◽  
Alejandro Strachan
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Ultrafast Lasers ◽  
Laser Energy ◽  
Laser Pulses ◽  
Fused Silica ◽  
Ultrafast Laser ◽  
Dynamics Simulation ◽  
Free Electrons ◽  
Ultrafast Laser Ablation

In recent decades, ultrafast lasers have been used successfully to micro-machine fused silica. The high intensity laser pulses first excite valence electrons to the conduction band via photoionization and avalanche ionization. The excited free electrons absorb laser energy, and transfer its energy to the ions, resulting in the temperature rise. This ionization leads to significant changes in Coulomb forces among the atoms. Both thermal and non-thermal (Coulomb explosion) ablation processes have been discussed in the literature [1]. This work applies molecular dynamics technique to study the interaction between ultrafast laser pulses and fused silica and the resulting ablation. The main goal of this work is to investigate the ultrafast laser ablation process of fused silica, and to reveal the mechanisms leading to the material's removal. In this MD simulation, the equilibrium state of fused silica is first established at 300 K, and the laser heating and material removal processes are simulated. The ionization of the material and the energy coupling between the laser beam and free electrons and ions are considered. Thermal and non-thermal mechanisms of fused silica ablation are discussed based on calculation results.

scholarly journals Laser induced ablation of aluminum nanoparticle: a molecular dynamics study

2018 ◽  
Vol 197 ◽  
pp. 04004 ◽  
Author(s):  
Riser Fahdiran ◽  
Erfan Handoko ◽  
Iwan Sugihartono ◽  
Herbert M. Urbassek
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
Molecular Dynamics Simulation ◽  
Laser Pulse ◽  
Equilibrium State ◽  
Ablation Threshold ◽  
Dynamics Simulation ◽  
High Intensity Laser ◽  
Cluster Properties ◽  
Intensity Laser

We investigate ablation of Aluminum nanoparticle due to ultrashort high-intensity laser pulse. Molecular dynamics simulation is used to follow the evolution of the system and observe thermodynamics together with cluster properties. The energy given from the laser to the system is 1.5 eV/atom which is above ablation threshold and modelled using instantaneous and homogenous energization at the beginning of simulation. The evolution of the system shows a highly non-equilibrium state after the irradiation. Expansion of the sphere indicated that the system cannot survive from the temporary high tensile pressure that leads to ablation. While the high temperature consecutively responsible for the formation of cluster, it also indicated that the system is relaxed at the end of the simulation.

Multicanonical Molecular Dynamics Simulation Study of the Liquid-Solid and Solid-Solid Transitions in Lennard-Jones Clusters

2011 ◽  
Author(s):  
Toshihiro Kaneko ◽  
Kenji Yasuoka ◽  
Ayori Mitsutake ◽  
Xiao Cheng Zeng
Keyword(s):  
Molecular Dynamics ◽  
Heat Capacity ◽  
Transition Temperature ◽  
Peak Position ◽  
Temperature Curve ◽  
Dynamics Simulation ◽  
Lennard Jones ◽  
Dynamics Simulations ◽  
First Time ◽  
Good Agreement

Multicanonical molecular dynamics simulations are applied, for the first time, to study the liquid-solid and solid-solid transitions in Lennard-Jones (LJ) clusters. The transition temperatures are estimated based on the peak position in the heat capacity versus temperature curve. For LJ31, LJ58 and LJ98, our results on the solid-solid transition temperature are in good agreement with previous ones. For LJ309, the predicted liquid-solid transition temperature is also in agreement with previous result.

Pressure Waves in Microscopic Simulations of Laser Ablation Leonid

1998 ◽  
Vol 538 ◽  
Author(s):  
V. Zhigilei ◽  
Barbara J. Garrison
Keyword(s):  
Boundary Condition ◽  
Laser Ablation ◽  
Laser Energy ◽  
Scale Up ◽  
Boundary Region ◽  
Dynamics Simulation ◽  
Pressure Waves ◽  
Absorption Region ◽  
Organic Solids ◽  
Direct Laser

AbstractLaser ablation of organic solids is a complex collective phenomenon that includes processes occurring at different length and time scales. A mesoscopic breathing sphere model developed recently for molecular dynamics simulation of laser ablation and damage of organic solids has significantly expanded the length-scale (up to hundreds of nanometers) and the time-scale (up to nanoseconds) of the simulations. The laser induced buildup of a high pressure within the absorbing volume and generation of the pressure waves propagating from the absorption region poses an additional challenge for molecular-level simulation. A new dynamic boundary condition is developed to minimize the effects of the reflection of the wave from the boundary of the computational cell. The boundary condition accounts for the laser induced pressure wave propagation as well as the direct laser energy deposition in the boundary region.

Preparation ZnO nanoparticles with Different Concentration by Laser Ablation in Liquid

2021 ◽  
Vol 39 (1B) ◽  
pp. 197-202
Author(s):  
Ghufran S. Jaber ◽  
Khawla S. Khashan ◽  
Maha J. Abbas
Keyword(s):  
Particle Size ◽  
Laser Ablation ◽  
Laser Pulse ◽  
Laser Energy ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Pulse Number ◽  
Average Particle ◽  
Zno Nps ◽  
Laser Ablation In Liquid

The effects of varying laser pulse numbers on the fabricated of ZnONPs by pulsed laser ablation in deionized water of Zn-metal are investigated. The Nd: YAG laser at energy 600mJ prepared three samples by change the laser pulse number (100, 150, and 200). The results were collected and examined using an electron scanning microscope, XRD – diffraction, and transmission electron microscope. The result revealed the colloidal spherical shape and the homogeneous composition of the ZnO NPs. The nanoparticles resulted in different concentrations and sized distributions by changing the pulse number of a laser. The average particle size and the mass concentration of particle size increase with an increasing number of laser pulses by fixed the laser energy.

Effect of silicon target porosity on laser ablation threshold: molecular dynamics simulation

2021 ◽  
Vol 18 (7) ◽  
pp. 076001
Author(s):  
A Yu Kharin ◽  
M S Grigoryeva ◽  
I N Zavestovskaya ◽  
V Yu Timoshenko
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Molecular Dynamics Simulation ◽  
Ablation Threshold ◽  
Dynamics Simulation ◽  
Silicon Target
Sign in / Sign up

Export Citation Format

Share Document