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Sputtering: Single Crystal Organic SIMS Cluster (C60) Bombardment Electronic Effects
Thermal Ablation Photochemical Ablation Coarse Grained Models
Organic Reactions and Mass Spectrometry - Organic SIMS
Gif picture       Collision induced surface mass spectrometric techniques such as secondary ion mass spectrometry (SIMS) and its sister technique fast atom bombardment mass spectrometry (FABMS) are continuing to be major techniques for analyzing large organic and biological molecules. We have been using molecular dynamics simulations to investigate the events that occur when energetic (~keV) particles bombard organic molecules. To date we have focused on single layers of organic molecules on metal and silicon substrates. A review of our results is given in a recent Accounts of Chemical Research article. The Accounts article highlights comparisons to experimental data. There are animations with organic molecules through the graphics link at the top of this page.

Molecular Ejection - Multiple Contact Points to the Surface
The predominant ejection mechanism for molecules with multiple contact points to the surface is one in which several atoms hit different parts of the molecule resulting in a cooperative uplifting of the intact unit. It is possible, however, for one substrate atom to eject the intact molecule.
Molecular Ejection - Upright Chain with Strong Binding to the Surface
Some particles must specifically move between the bottom atom in the adsorbate molecule and the substrate in order to eject the tightly bound molecule intact. This motion tends to be a low probability event and consequently there is relatively little intact molecular ejection. The prediction of the calculations is that the top part of the chain is a major fragment species.
Molecular Ejection - Upright Chain with Weak Binding to the Surface
If the binding energy of the molecule to the solid is sufficiently small, then molecular ejection can occur when a particle strikes the middle of the adsorbed molecule.
Megaevents and Ejection of Large Molecules
There are some impacts in which considerable motion occurs. It is these megaevents that can give rise to as much as 10000 amu ejecting in the simulations.
Reactions between Two Molecules
The calculations predict that reactions between a fragment of one molecule and another molecule can readily occur during one bombardment event.
Reactions - Unimolecular Rearrangements
The calculations predict that unimolecular rearrangements can occur in both the sub-picosecond and the microsecond time frames.
Reactions - Metal-Thiolate Clusters
The association of a metal atom with an ejected molecule in the vicinity of the surface occurs in the sub-picosecond time scale.
SIMS Molecular Fragment Distributions
For organic molecules adsorbed on metal substrates, the fragments observed in the MD simulations often mirror the experimental SIMS spectra.
Energy and Angular Distributions
The kinetic energy distributions of fragments detected in SIMS experiments are also well predicted by the MD model. The key feature here is to correct the calculated distributions to account for the metastable decay reactions occurring in the gap between the picosecond time scale of the simulation and the microsecond timescale of the experiment. A realistic correction is achieved using the RRK theory. See Ref. 195 for further details. Reality checks on the simulations are also performed by comparison with energy and angular distributions as measured with multiphoton ionization techniques. In this respect, benzene molecules adsorbed on Ag{111} surface has been the system of choice for many years.
Polyatomic Projectile Beams
Yield enhancement

Bombardment of organic surfaces by keV polyatomic projectiles leads to a dramatic increase of the molecular ion yields.
Collaborating Collision Cascades

Polyatomic projectiles increase the probability of adjacent collision cascades, which collaborate to gently lift the intact molecule off of the surface.
Substrate Effect

Our results show that it is a unique coupling between the structure of the sample and the incident projectile that determines whether cluster bombardment provides a meaningful improvement in the information content of the mass spectrum. In particular, we predict that the greatest enhancements will be found for polyatomic projectiles impinging on highly open lattices, and that more dense, metallic-like substrates will be less efficient. Therefore, polyatomic projectiles should greatly improve the performances of SIMS for the analysis of bulk organic samples.

Silicon Substrate:

On silicon, SF5 is able to break up within the silicon lattice, which leads to the upward movement of substrate atoms beneath to biphenyl overlayer.

Copper Substrate:

On copper, SF5 breaks apart upon the surface, which is ineffective in ejecting molecules from the surface.

Animations courtesy of Kristin Krantzman, College of Charleston.

Multiple Frame Pictures from Simulations
Help yourself to these pictures but please give us credit.
Organic SIMS Publications

256.

Emission Of Ionic Water Clusters From Water Ice Films Bombarded By Energetic Projectiles, I. A. Wojciechowski, U. Kutliev, S. Sun, C. Szakal, N. Winograd, and B. J. Garrison, SIMS XIV Proceedings, Appl. Surf. Sci., 231-232, 72-77 (2004). [full-article - PDF]

255.

Sputtering of Ag under C60+ and Ga+ Projectile Bombardment, S. Sun, C. Szakal, E. J. Smiley, Z. Postawa, A. Wucher, B.J. Garrison, N. Winograd, SIMS XIV Proceedings, Appl. Surf. Sci., 231-232, 64-67 (2004). [full-article - PDF]

254.

Sputtering Of A Polycyclic Hydrocarbon Molecule: Tof-Sims Experiments And Molecular Dynamic Simulations, V.Solomko, A. Delcorte, B.J. Garrison and P. Bertrand, SIMS XIV Proceedings, Appl. Surf. Sci., 231-232, 48-53 (2004). [full-article - PDF]

253.

A Comparison Of Molecular Dynamic Simulations And Experimental Observations: The Sputtering Of Gold {100} By 20 Kev Argon, C.M. McQuaw, E.J. Smiley, B.J. Garrison and N. Winograd, SIMS XIV Proceedings, Appl. Surf. Sci., 231-232, 39-43 (2004). [full-article - PDF]

252.

Microscopic Insights into the Sputtering of Ag{111} Induced by C60 and Ga Bombardment of Ag{111}, Z. Postawa, B. Czerwinski, M. Szewczyk, E. J. Smiley, N. Winograd and B. J. Garrison, J. Phys. Chem. B, 108, 7831-7838 (2004) [full-article - PDF]

250.

Ion Emission from Water Ice due to Energetic Particle Bombardment, I. A. Wojciechowski, S. Sun, C. Szakal, N. Winograd, and B. J. Garrison, J. Phys. Chem. A, Issue in honor of H. F. Schaefer III, 108, 2993-2998 (2004). [full article - PDF]

246.

Enhancement of Sputtering Yields due to C60 vs. Ga Bombardment of Ag{111} as Explored by Molecular Dynamics Simulations, Z. Postawa, B. Czerwinski, M. Szewczyk, E. J. Smiley, N. Winograd and B. J. Garrison, Analytical Chemistry, 75, 4402-4407 (2003).[full article - PDF]

245.

Gold-thiolate cluster emission from SAMs under keV ion bombardment: Experiments and Molecular Dynamics Simulations., B. Arezki, A. Delcorte, A. C. Chami, B. J. Garrison, and P. Bertrand, Nucl. Instrum. Methods B, 212, 369-375 (2003).[full article - PDF]

244.

Matrix and Substrate Effects on the Sputtering of a 2 kDa Molecule: Insights from Molecular Dynamics, A. Delcorte, B. Arezki and B. J. Garrison, Nucl. Instrum. Methods B, 212, 414-419 (2003).[full article - PDF]

243.

Theoretical study of mechanisms responsible for emission of highly excited metal atoms, I. Wojciechowski and B. J. Garrison, Surface Science, 527, 209-218 (2003).[full article - PDF]

242.

Microscopic mechanisms in matrix:analyte sample sputtering, A. Delcorte and B. J. Garrison, Journal of Physical Chemistry B, 107, 2297-2310 (2003).[full article - PDF]

237.

Molecular Dynamic Simulations of the Sputtering of Multilayer Organic Systems, Z. Postawa, K. Ludwig, J. Piaskowy, K. Krantzman, N. Winograd and B.J. Garrison, Nucl. Instrum. Methods B, 203, 168-174 (2003).[full article - PDF]

236.

Theoretical Simulations of Atomic and Polyatomic Bombardment of an Organic Overlayer on a Metallic Substrate, K. D. Krantzman, R. Fenno, A. Delcorte and B. J. Garrison, Nucl. Instrum. Methods B, 203, 201-205 (2003).[full article - PDF]

230.

Effect of Mass and Incidence Angle of keV Energy Polyatomic Projectiles in Silicon Sputtering, M. Medvedeva, I. Wojciechowski and B. J. Garrison, Surface Science, 505, 349-357 (2002).[full article - PDF]

229.

The formation of singly and doubly cationized oligomers in SIMS, SIMS-XIII Proceedings, A. Delcorte, I. Wojciechowski, X. Gonze, B. J. Garrison and P. Bertrand, Appl. Surf. Sci., 203-204, 106-109 (2003).[full article - PDF]

228.

Enhancement of Cluster Yield under Gold Dimer Oblique Bombardment of the Silicon Surface, SIMS-XIII Proceedings, M. Medvedeva, I. Wojciechowski and B. J. Garrison, Appl. Surf. Sci., 203-204, 148-151 (2003).[full article - PDF]

227.

Molecular SIMS for organic layers: new insights, P. Bertrand, A. Delcorte, and B. J. Garrison, SIMS-XIII Proceedings, Appl. Surf. Sci., 203-204, 160-165 (2003).[full article - PDF]

226.

Big Molecule Ejection - SIMS vs. MALDI, B. J. Garrison, A. Delcorte, L. V. Zhigilei, T. E. Itina, K. D. Krantzman, Y. G. Yingling, C. M. McQuaw, E. J. Smiley and N. Winograd, SIMS-XIII Proceedings, Appl. Surf. Sci., 203-204, 69-71 (2003).[full article - PDF]

225.

A Microscopic View of Organic Sample Sputtering, A. Delcorte, P. Bertrand, and B. J. Garrison, SIMS-XIII Proceedings, Appl. Surf. Sci.,203-204, 166-169 (2003).[full article - PDF]

223.

Modeling sputtering of organic molecules, B. J. Garrison, A. Delcorte, and K. D. Krantzman, Izvestiya Akademii Nauk - ser. fizika, 66, 472-474 (2002).[full article - PDF]

222.

Sputtering Kilodalton Fragments from Polymers, A. Delcorte, B. Arezki, P. Bertrand, and B. J. Garrison,, Nucl. Instrum. Methods Phys. Research B, 193, 768-774 (2002).[full article - PDF]

220.

Single and Double Cationization of Organic Molecules in SIMS, A. Delcorte, I. Wojciechowski, X. Gonze, B. J. Garrison, and P. Bertrand, Int. J. Mass Spectrom., 213, 213-232 (2002).[full article - PDF]

217.

Self-Sputtering of Silver by Mono- and Polyatomic Projectiles: A Molecular Dynamics Investigation, M. Lindenblatt, R. Heinrich, A. Wucher and B. J. Garrison, J. Chem. Phys., 115, 8643-8654 (2001).[full article - PDF]

214.

Molecular Desorption and SIMS, N. Winograd and B. J. Garrison, Int. J. Mass Spectrom, R. G. Cooks special issue, 212, 467-475 (2001).[full article - PDF]

212.

Collision Cascade and Sputtering Process in a Polymer, A. Delcorte, P. Bertrand and B. J. Garrison, J. Phys. Chem. B, 105, 9474-9486 (2001).[full article - PDF]

208.

Desorption of silver atoms from benzene-covered Ag(111) by energetic Ar+ bombardment, C. A. Messerole, E. Vandeweert, Y. Dou, Z. Postawa, B. J. Garrison, and N. Winograd, Nucl. Instrum. Methods Phys. Research B, 180, 53-57 (2001).[full article - PDF]

206.

Desorption of large organic molecules induced by keV projectiles, A. Delcorte and B. J. Garrison, Nucl. Instrum. Methods Phys. Research B,180, 37-43 (2001).[full article - PDF]

203.

Understanding Collision Cascades in Molecular Solids, K. D. Krantzman, Z. Postawa, B. J. Garrison, N. Winograd, S. J. Stuart, and J. A. Harrison, Nucl. Instrum. Methods Phys. Research B, 180, 159-163 (2001).[full article - PDF]

200.

Molecular Dynamics Simulations, the Theoretical Partner to Static SIMS Experiments, B. J. Garrison, in ToF-SIMS: Surface Analysis by Mass Spectrometry, edited by J. C. Vickerman and D. Briggs, SurfaceSpectraLtd & IMPublications, September (2001). SurfaceSpectraLtd

199.

A Theoretical Investigation of the Yield-to-Damage Enhancement with Polyatomic Projectiles in Organic SIMS, T. C. Nguyen, D. W. Ward, J. A. Townes, A. K. White, K. D. Krantzman, and B. J. Garrison, J. Phys. Chem B, 104, 8221-8228 (2000).[full article - PDF]

198.

High Yield events of molecule emission induced by keV particle bombardment, A. Delcorte and B. J. Garrison, J. Phys. Chem. B, 104, 6785-6800 (2000).[full article - PDF]

197.

Inferring Ejection Distances and a Surface Energy Profile in keV Particle Bombardment Experiments, A. Delcorte, B. G. Segda, B. J. Garrison, and P. Bertrand, Nucl. Instrum. Methods Phys. Research B, 171, 277-290 (2000). [full article - PDF]

195.

KeV Particle-induced Emission and Fragmentation of Polystyrene Molecules Adsorbed on Silver: Insights from Molecular Dynamics, A. Delcorte, X. Vanden Eynde, P. Bertrand, J. C. Vickerman, and B. J. Garrison, J. Phys. Chem. B, 104, 2673-2691 (2000).[full article - PDF]

194.

Molecule Liftoff from Surfaces, B. J. Garrison, A. Delcorte and K. D. Krantzman, Accts. Chem. Res., 33, 69-77 (2000). [full article - PDF]

192.

Resonant Postionization of Neutral Species Desorbed by keV Ar+ Bombardment of C6H6/Ag(111), C. A. Meserole, E. Vanderwert, R. Chatterjee, A. Sostarecz, B. J. Garrison, N. Winograd and Z. Postawa, Proceedings of the 12th International Conference on Secondary Ion Mass Spectrometry, edited by A. Benninghoven, P. Bertrand, H-N. Migeon and H. W. Werner, 321-324 (2000).[full article - PDF]

191.

A Comparison of the Energy Density Distribution with Atomic and Polyatomic Projectiles in Organic SIMS, D. W. Ward, T. C. Nguyen, K. D. Krantzman and B. J. Garrison, Proceedings of the 12th International Conference on Secondary Ion Mass Spectrometry, edited by A. Benninghoven, P. Bertrand, H-N. Migeon and H. W. Werner, 183-186 (2000).[full article - PDF]

190.

How Do Large Organic Molecules Sputter? Insights from TOF-SIMS and Molecular Dynamics Simulations, A. Delcorte, P. Bertrand, J. C. Vickerman and B. J. Garrison, Proceedings of the 12th International Conference on Secondary Ion Mass Spectrometry, edited by A. Benninghoven, P. Bertrand, H-N. Migeon and H. W. Werner, 27-32 (2000).[full article - PDF]

189.

Mechanism for Increased Yield with SF5+ Projectiles in Organic SIMS: The Substrate Effect, J. A. Townes, A. K. White, E. N. Wiggins, K. D. Krantzman, B. J. Garrison, and N. Winograd, J. Phys. Chem. A, 103, 4587-4589 (1999). [full article - PDF]

187.

Molecular Dynamics Simulations of Organic SIMS with Cun (n=1-3) Clusters, J. A. Townes, A. K. White, K. D. Krantzman and B. J. Garrison, Proceedings for the 15th International Conference on the Application of Accelerators in Research and Industry, edited by J. L. Duggan and I. L. Morgan, 401-404 (1999). [full article - PDF]

184.

Molecular Dynamics Simulations of Particle Bombardment Induced Desorption Processes: Alkanethiolates on Au(111), K. S. S. Liu, C. W. Yong, B. J. Garrison and J. C. Vickerman, J. Phys. Chem. B, 103, 3195-3205 (1999). [full article - PDF]

183.

Molecular Dynamics Simulation Study of Molecular Ejection Mechanisms: keV Particle-bombardment of C6H6/Ag {111}, R. Chatterjee, Z. Postawa, N. Winograd and B.J. Garrison, J. Phys. Chem., 103, 151-163 (1999). [full article - PDF]

179.

State-selective Laser Photo Ionization Of Neutral Benzene Molecules Ejected From keV Ion Bombarded C6H6/Ag {111}, C. A. Meserole, E. Vandeweert, R. Chatterjee, B. R. Chakraborty, B. J. Garrison, N. Winograd, and Z.Postawa, Resonance Ionization Spectroscopy, J.C. Vickerman, I. Lyon, N. P. Lockyer and J. E. Parks editors, AIP Conference Proc. 454, 210-213 (1998). [full article - PDF]

171.

Molecular Dynamics Simulations of Organic Sims with Cluster Projectiles, R. Zaric, B. Pearson, K. D. Krantzman and B. J. Garrison, Secondary Ion Mass Spectrometry, SIMS XI, G. Gillen, R. Lareau, J. Bennet and F. Stevie Editors, 601-604 (1998). [full article - PDF]

170.

Mechanistic Study of Particle Bombardment of an Alkanethiolate/Au System, K. S. S. Liu, J. C. Vickerman and B. J. Garrison, Secondary Ion Mass Spectrometry, SIMS XI, G. Gillen, R. Lareau, J. Bennet and F. Stevie Editors, 443-446 (1998). [full article - PDF]

162.

Pushing the Limits of Classical Modeling of Bombardment Events in Solids, R. Chatterjee and B. J. Garrison, Radiat. Eff. Defects Solids, 142, 585-603 (1997). [full article - PDF]

159.

Computer Simulation of Particle Bombardment of Alkanethiol Chains Adsorbed on Gold Surface, K. S. S. Liu, J. C. Vickerman and B. J. Garrison, Radiat. Eff. Defects Solids, 142, 663-679 (1997). [full article - PDF]

153.

Molecular Dynamics Simulations of Reactions Between Molecules: High Energy Particle Bombardment of Organic Films, B. J. Garrison and R. S. Taylor, Secondary Ion Mass Spectrometry, SIMS X, (John Wiley & Sons, 1997), 951-964. [full article - PDF]

151.

Modeling of Surface Processes as Exemplified by Hydrocarbon Reactions, B. J. Garrison, P. B. S. Kodali and D. Srivastava, Chemical Reviews 96, 1327-1341 (1996). [full article - PDF]

150d.

Desorption Mechanism of Benzene from C6H6/Ag(111) Using keV Ion Bombardment and Laser Postionization, R. Chatterjee, D. E. Riederer, B. J. Garrison, N. Winograd and Z. Postawa, AIP Conf. Proc. 338, 375-378 (1997). [full article - PDF]

148.

Potential Energy Surfaces for Chemical Reactions at Solid Surfaces, B. J. Garrison and D. Srivastava, Ann. Rev. Phys. Chem. 46, 373-394 (1995). [full article - PDF]

145.

A Microscopic View of keV Particle Bombardment of Organic Films, R. S. Taylor and B. J. Garrison, Int. J. Mass Spec. Ion Proc. 143, 225-233 (1995). [full article - PDF]

144.

Molecular Dynamics Simulations of keV Particle Bombardment: Correlation of Intact Molecular Ejection with Adsorbate Size, R. S. Taylor and B. J. Garrison, Chem. Phys. Lett. 230, 495-500 (1994). [full article - PDF]

143.

Molecular Desorption in Bombardment Mass Spectrometries, R. S. Taylor, C. L. Brummel, N. Winograd, B. J. Garrison, J. C. Vickerman, Chem. Phys. Lett. 233, 575-579 (1995). [full article - PDF]

141.

Molecular Dynamics Simulations of Reactions Between Molecules: High Energy Particle Bombardment of Organic Films, R. S. Taylor and B. J. Garrison, Langmuir 11, 1220-1228 (1995). [full article - PDF]

136.

Hydrogen Abstraction Reactions in the keV Particle Bombardment of Organic Films, R. S. Taylor and B. J. Garrison, J. Am. Chem. Soc., 116, 4465-4466 (1994). [full article - PDF]

123.

Molecular Dynamics Simulations of Surface Chemical Reactions, B. J. Garrison, Chem. Soc. Reviews, Vol. 21, 155-162 (1992). [full article - PDF]

100.

Surface Structure and Reaction Studies by Ion-Solid Collisions, N. Winograd and B. J. Garrison, in "Methods of Surface Characterization", Vol. 2, ed. A. W. Czanderna and D. M. Hercules (Plenum Press, NY, 1991), 45-141. [full article - PDF]

72.

A Classical Dynamics Study of the Ion Bombardment of Ice, D. W. Brenner and B. J. Garrison, Phys. Rev. B34, 5782-5787 (1986). [full article - PDF]

54.

Mechanisms of Organic Molecule Ejection in SIMS and FABMS Experiments, B. J. Garrison, Springer Series in Chem. Physics, Vol. 36, p 363-365, Springer-Verlag, Berlin (1984). [full article - PDF]

47.

A Classical Dynamics Model of Plasma Desorption Mass Spectrometry Experiments, B. J. Garrison, J. Am. Chem. Soc. 105, 373-378 (1983).[full article - PDF]

46.

Organic Molecule Ejection from Surfaces due to Heavy Particle Bombardment, B. J. Garrison, J. Am. Chem. Soc. 104, 6211-6217 (1982).[full article - PDF]

37.

Mechanisms of Ejection due to Ion Bombardment: c(4x4) Overlayer of Benzene on Ni(001), B. J. Garrison, Le Vide, le Couches Minces 201, 1411-1414 (1980).[full article - PDF]

36.

Mechanisms of Ejection of Organic Molecules from Surfaces by keV Ion Bombardment, B. J. Garrison, J. Am. Chem. Soc. 102, 6553-6555 (1980).[full article - PDF]

25.

Mechanisms of CO Ejection from Ion Bombarded Single Crystal Surfaces, N. Winograd, B. J. Garrison, and D. E. Harrison, Jr., J. Chem. Phys. 73, 3473-3479 (1980).[full article - PDF]


Leonid V. Zhigilei & Arnaud D. Delcorte - October 15, 1997 / Last updated (bjg) - December 20, 2003