Pushing the limits of classical modeling of bombardment events in solids

Chatterjee, R.; Garrison, Barbara J.

doi:10.1080/10420159708211602

Cited by 10 publications

(5 citation statements)

References 42 publications

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Section: Resultssupporting

confidence: 66%

“…This conclusion is further supported by molecular dynamics simulation results of ion bombardment of a (3 × 3) overlayer of C 6 H 6 on Ag{111}. The simulations show that the energy distributions of the ejected C 6 H 6 are comparable to that of Ag, 37 and a majority of C 6 H 6 ejection is stimulated by collisions with these particles. As the exposure is increased above 1 langmuir, the peak position in the kinetic energy distribution of C 6 H 6 molecules successively decreases from 1 to 0.25 eV at 6 langmuirs.…”

Section: Resultssupporting

confidence: 52%

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Coverage-Dependent Molecular Ejection from Ion-Bombarded C₆H₆/Ag{111}

et al. 1998

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Time-of-flight distributions, angular distributions, and relative sputtering yields of neutral benzene (C 6 H 6 ) molecules ejected from submonolayer to multilayer coverage of C 6 H 6 on Ag{111} have been measured after 8 keV ion bombardment. Two components are present in the time-of-flight distributions obtained using Ar + ion as the projectile. For low coverage a peak corresponding to kinetic energies ranging between 0.25 and 1 eV dominates the distribution, whereas for multilayer coverage a peak corresponding to extremely low kinetic energy (0.04 eV) becomes dominant. The total yield of the ejected neutral C 6 H 6 molecules is largest for a monolayer coverage and decreases to ∼50% of the maximum for multilayer samples. For low coverage, the C 6 H 6 kinetic energy and angular distributions take on the same characteristics as that of silver particles ejecting from the substrate, indicating that collisions originating in the metal substrate lead to the ejection of C 6 H 6 molecules. The low kinetic energy emission of molecules from the multilayer films is proposed to occur due to exothermic chemical reaction of fragments formed in a molecular collision cascade initiated by the projectile ions. Finally, for the entire coverage range investigated, no C 6 H 6 signal is observed when H 2 + ion is used as the projectile, indicating that a momentum-transfer process is important in the ejection of C 6 H 6 molecules.

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Section: Resultssupporting

confidence: 66%

Section: Resultssupporting

confidence: 52%

Coverage-Dependent Molecular Ejection from Ion-Bombarded C₆H₆/Ag{111}

et al. 1998

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“…57 The potential has also been used in the particle bombardment studies where chemical reactions are modeled among adsorbed molecules supported on a metal. [16][17][18][19][20]38,39,48,[61][62][63] Of note is that this hydrocarbon potential is confined only to short-range interactions of nearest neighbors. Any long-range van der Waals type interactions are not included.…”

Section: Methodsmentioning

confidence: 99%

Molecular Dynamics Simulations of Particle Bombardment Induced Desorption Processes: Alkanethiolates on Au(111)

et al. 1999

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Molecular dynamics has been used to model Ar atom induced sputtering of n-alkanethiolate molecules self-assembled on Au(111). The aim is to discover possible mechanisms of formation of the various sputtered species such that their relationship to surface chemistry can be understood. To model the system, a blend of pairwise and many-body potentials are used to represent the interatomic interactions. To simulate the formation of gold−thiolate clusters required the development of the potential for the Au−S interaction. The resulting model predicted a “mass spectrum” of atomic and cluster species which is remarkably similar to the experimental static SIMS spectra of n-alkanethiolate SAMs on gold. A number of emission mechanisms for the production of hydrocarbon fragments and gold−thiolate clusters are suggested by the model which provide very valuable insights into the relationship between the spectral features and surface chemistry.

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“…Molecular dynamics simulations and experiments of kiloelectronvolt ion bombardment of C 6 H 6 /Ag{111} have shown that the kinetic energy distributions of the ejected neutral benzene and silver are similar. 21 Collisions originating in the silver substrate lead to the ejection of benzene molecules with energies around 1 eV. The ejection of phenylethanethiol molecules with energies around 1 eV (peak A, Figure 2) is due to a ballistic process.…”

Section: Resultsmentioning

confidence: 98%

“…The collision cascade model for atomic solids provides an analytical expression for kinetic energy distributions of sputtered atomic species. , Though it cannot be directly applied to molecular ejection, similarity between the energy distributions of substrate atoms and adsorbate molecules can be used to correlate the ejection of molecules to a ballistic process. Molecular dynamics simulations and experiments of kiloelectronvolt ion bombardment of C 6 H 6 /Ag{111} have shown that the kinetic energy distributions of the ejected neutral benzene and silver are similar …”

Section: Resultsmentioning

confidence: 99%

Thermal Desorption Induced by Kiloelectronvolt Ion Bombardment of Thiol-Bound Self-Assembled Monolayers on Gold

et al. 1997

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Time distributions of neutral molecules desorbed from a chemisorbed self-assembled monolayer of phenylethanethiol on gold have been measured subsequent to 8 keV Ar + and H 2 + ion bombardment. These distributions show that, regardless of the projectile used, most of the ejected molecules leave the surface with thermal kinetic energies (∼0.03 eV). The shapes of the distributions have a strong surface temperature dependence over the range 240-300 K. This behavior is well described by a convolution of the Maxwell-Boltzmann distribution and the rate equation for first-order desorption. The results imply that kiloelectronvolt ion bombardment initiates a process which breaks the adsorbate-surface bond, leaving the resulting physisorbed molecules to evaporate after attaining thermal equilibrium with the substrate. A mechanism for this gentle cleavage of the adsorbate-substrate bond is proposed.

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Pushing the limits of classical modeling of bombardment events in solids

Cited by 10 publications

References 42 publications

Coverage-Dependent Molecular Ejection from Ion-Bombarded C₆H₆/Ag{111}

Coverage-Dependent Molecular Ejection from Ion-Bombarded C₆H₆/Ag{111}

Molecular Dynamics Simulations of Particle Bombardment Induced Desorption Processes: Alkanethiolates on Au(111)

Thermal Desorption Induced by Kiloelectronvolt Ion Bombardment of Thiol-Bound Self-Assembled Monolayers on Gold

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Pushing the limits of classical modeling of bombardment events in solids

Cited by 10 publications

References 42 publications

Coverage-Dependent Molecular Ejection from Ion-Bombarded C6H6/Ag{111}

Coverage-Dependent Molecular Ejection from Ion-Bombarded C6H6/Ag{111}

Molecular Dynamics Simulations of Particle Bombardment Induced Desorption Processes: Alkanethiolates on Au(111)

Thermal Desorption Induced by Kiloelectronvolt Ion Bombardment of Thiol-Bound Self-Assembled Monolayers on Gold

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Coverage-Dependent Molecular Ejection from Ion-Bombarded C₆H₆/Ag{111}

Coverage-Dependent Molecular Ejection from Ion-Bombarded C₆H₆/Ag{111}