Ranges and fragmentation behavior of fullerene molecules: A molecular-dynamics study of the dependence on impact energy and target material

Anders, Christian; Kirihata, Hiroaki; Yamaguchi, Yasutaka; Urbassek, Herbert M.

doi:10.1016/j.nimb.2006.11.027

Cited by 28 publications

(32 citation statements)

References 27 publications

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“…In fact, a 4 layer LB film is not thick enough to stop many of these atoms. The calculations performed on a 6 layer system show that the penetration of 15 keV projectile atoms can extend up to 14 nm into the organic film, a depth 4-5 times larger than for keV C 60 in materials like graphite,11,17 fullerite,17 molecular benzene,14,35 water ice,16 or polymer samples18,19. All previous theoretical studies with C 60 projectiles have shown that the projectile atoms are almost immediately decelerated and the primary energy is deposited close to the surface 10-12,14-19,31,35.…”

Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Simulations of Sputtering of Langmuir−Blodgett Multilayers by Kiloelectronvolt C₆₀ Projectiles

et al. 2009

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Coarse-grained molecular dynamics computer simulations are applied to investigate fundamental processes induced by an impact of keV C 60 projectile at an organic overlayer composed of long, well-organized linear molecules. The energy transfer pathways, sputtering yields, and the damage induced in the irradiated system, represented by a Langmuir-Blodgett (LB) multilayers composed from molecules of bariated arachidic acid, are investigated as a function of the kinetic energy and impact angle of the projectile and the thickness of the organic system. In particular, the unique challenges of depth profiling through a LB film vs. a more isotropic solid are discussed.The results indicate that the trajectories of projectile fragments and, consequently, the primary energy can be channeled by the geometrical structure of the overlayer. Although, a similar process is known from sputtering of single crystals by atomic projectiles, it has not been anticipated to occur during C 60 bombardment due to the large size of the projectile. An open and ordered molecular structure of LB films is responsible for such behavior. Both the extent of damage and the efficiency of sputtering depend on the kinetic energy, the impact angle, and the layer thickness. The results indicate that the best depth profiling conditions can be achieved with low-energy cluster projectiles irradiating the organic overlayer at large off-normal angles.

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Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Simulations of Sputtering of Langmuir−Blodgett Multilayers by Kiloelectronvolt C₆₀ Projectiles

et al. 2009

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“…For example, atomic dissociation in the covalently bonded fullerene projectile, C 60 , only starts at impact energies exceeding 8.3 eV per atom. 24 The dimensions of the silicon slab are adjusted with the droplet's diameter to minimize boundary effects. The target for the 5 nm droplet is a 32.59 nm Â 32.59 nm Â 24.44 nm parallelepiped (1, 303, 200 Si atoms, the shorter dimension is in the direction of the impact), while the target for the 30 nm droplet is a larger 130.34 nm Â 130.34 nm Â 97.76 nm slab (83, 059, 200 Si atoms).…”

Section: Simulation Methodsmentioning

confidence: 99%

Atomistic modeling of the sputtering of silicon by electrosprayed nanodroplets

Saiz

Gamero-Castaño

2014

Journal of Applied Physics

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The hypervelocity impact of electrosprayed nanodroplets on single-crystal silicon ejects a large number of atoms. Although sputtering by atomic, molecular, and gas cluster ions has been thoroughly studied, the significantly larger size of nanodroplets prevents a straightforward extrapolation of the physics governing the impact of these smaller projectiles. This motivates the present molecular dynamics simulations of nanodroplet impact on silicon, aimed at resolving the mechanisms and the effect of the projectile's size and velocity on sputtering. We find that both collision cascades and thermal sputtering contribute to the overall atom ejection, the former being active during the initial stages of the impact characterized by strong interactions between the molecules of the projectile and the atoms of the target, and the absence of partial thermodynamic equilibrium. In addition, for sufficiently large projectile diameters and impact velocities, conglomerates of atoms are ejected by hydrodynamic forces. The sputtering yield, defined as the average number of target atoms ejected per projectile's molecule, increases monotonically with the kinetic energy of the molecules and, at constant molecular kinetic energy, slightly decreases with projectile diameter as a result of enhanced backscattering of the ejected atoms by the projectile's molecules. For the ionic liquid considered in this study, sputtering is first observed at molecular energies near 12.7 eV and, at the highest energy simulated of 73 eV, the sputtering yield averages to 0.37. V C 2014 AIP Publishing LLC. [http://dx.

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“…Recent reviews of the simulation of cluster impacts on molecular solids1–2 and other materials3–4 demonstrate that these normally result in the formation of a crater. The crater is formed by the compression of the material around the initial impact and the ejection of both fragments and intact molecular species from the region.…”

Section: Introductionmentioning

confidence: 99%

The effect of the H:C ratio on the sputtering of molecular solids by fullerenes

Webb

Garrison

Vickerman

2011

Surface & Interface Analysis

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The understanding of the process by which molecular solids are sputtered by keV clusters such as C 60 is of great importance if cluster SIMS is to be routinely used to depth profile a wide range of molecular materials. Computer simulations of the impact of a C 60 cluster on a molecular solid show that an impact crater is produced. At the edges of the crater, a reaction zone is created which contains fragmented and cross-linked molecules. It has been shown previously that this 'reaction zone' can be extensive for a molecular material like fullerite, and yet, for benzene it appears to be smaller. It is well known that fullerite cross-links through cycloaddition under compression in which the normal sp 2 bonding in the fullerene molecules takes on a tetragonal sp 3 pattern when two molecules are forced together creating a strong cross-link between them. It is this process which leads to such an extensive reaction zone after impact. The presence of hydrogen in other molecular systems could resist this process. The purpose of the investigation reported here is to observe the nature of the reaction zone for different molecular systems with varying hydrogen content and different initial coordination. Molecular dynamics simulations of molecular solids of octane, octatetraene, benzene and fullerite struck by 15 keV C 60 were performed. Octane is initially four-fold coordinated, whilst the other molecular solids are all three-fold coordinated. The reaction zone of the crater formed by the impact was measured and it was concluded that the H : C ratio influences the nature of the reaction zone, whereas the initial coordination has only a secondary effect on the reaction zone.

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Ranges and fragmentation behavior of fullerene molecules: A molecular-dynamics study of the dependence on impact energy and target material

Cited by 28 publications

References 27 publications

Molecular Dynamics Simulations of Sputtering of Langmuir−Blodgett Multilayers by Kiloelectronvolt C₆₀ Projectiles

Molecular Dynamics Simulations of Sputtering of Langmuir−Blodgett Multilayers by Kiloelectronvolt C₆₀ Projectiles

Atomistic modeling of the sputtering of silicon by electrosprayed nanodroplets

The effect of the H:C ratio on the sputtering of molecular solids by fullerenes

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Ranges and fragmentation behavior of fullerene molecules: A molecular-dynamics study of the dependence on impact energy and target material

Cited by 28 publications

References 27 publications

Molecular Dynamics Simulations of Sputtering of Langmuir−Blodgett Multilayers by Kiloelectronvolt C60 Projectiles

Molecular Dynamics Simulations of Sputtering of Langmuir−Blodgett Multilayers by Kiloelectronvolt C60 Projectiles

Atomistic modeling of the sputtering of silicon by electrosprayed nanodroplets

The effect of the H:C ratio on the sputtering of molecular solids by fullerenes

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Product

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Molecular Dynamics Simulations of Sputtering of Langmuir−Blodgett Multilayers by Kiloelectronvolt C₆₀ Projectiles

Molecular Dynamics Simulations of Sputtering of Langmuir−Blodgett Multilayers by Kiloelectronvolt C₆₀ Projectiles