Classical trajectories and RRKM modeling of collisional excitation and dissociation of benzylammonium and tert-butyl benzylammonium ions in a quadrupole-hexapole-quadrupole tandem mass spectrometer



Collision-induced dissociation of the benzylammonium and the 4-tert-butyl benzylammonium ions was studied experimentally in an electrospray ionization quadrupole-hexapole-quadrupole tandem mass spectrometer. Ion fragmentation efficiencies were determined as functions of the kinetic energy of ions and the collider gas (argon) pressure. A theoretical Monte Carlo model of ion collisional excitation, scattering, and decomposition was developed. The model includes simulation of the trajectories of the parent and the product ions flight through the hexapole collision cell, quasiclassical trajectory modeling of collisional activation and scattering of ions, and Rice-Ramsperger-Kassel-Marcus (RRKM) modeling of the parent ion decomposition. The results of modeling demonstrate a general agreement between calculations and experiment. Calculated values of ion fragmentation efficiency are sensitive to initial vibrational excitation of ions, scattering of product ions from the collision cell, and distribution of initial ion velocities orthogonal to the axis of the collision cell. Three critical parameters of the model were adjusted to reproduce the experimental data on the dissociation of the benzylammonium ion: reaction enthalpy and initial internal and translational temperatures of the ions. Subsequent application of the model to decomposition of the t-butyl benzylammonium ion required adjustment of the internal ion temperature only. Energy distribution functions obtained in modeling depend on the average numbers of collisions between the ion and the atoms of the collider gas and, in general, have non-Boltzmann shapes.


  1. 1.
    Chapman, J. R. Mass Spectrometry of Protein and Peptides; Humana Press: Totowa, NJ, 2000.CrossRefGoogle Scholar
  2. 2.
    Glish, G. L.; Vachet, R. W. The basics of mass spectrometry in the twenty-first century. Nat. Rev. Drug Dic. 2003, 2, 140–150.CrossRefGoogle Scholar
  3. 3.
    Lin, D.; Tabb, D. L.; Yates, J. R. I. Large-Scale Protein Identification Using Mass Spectrometry. Biochim. Biophys. Acta. 2003, 1646, 1–10.CrossRefGoogle Scholar
  4. 4.
    Aebersold, R. A Mass Spectrometric Journey into Protein and Proteome Research. J. Am. Soc. Mass Spectrom. 2003, 14, 685–695.CrossRefGoogle Scholar
  5. 5.
    McLuckey, S. A.; Wells, J. M. Mass Analysis at the Advent of the 21st Century. Chem. Rev. 2001, 101, 571–606.CrossRefGoogle Scholar
  6. 6.
    Shukla, A. K.; Futrell, J. H. Tandem Mass Spectrometry: Dissociation of Ions by Collisional Activation. J. Mass Spectrom. 2000, 35, 1069–1090.CrossRefGoogle Scholar
  7. 7.
    McLuckey, S. A. Principles of Collisional Activation in Analytical Mass Spectrometry. J. Am. Soc. Mass Spectrom. 1992, 3, 559–614.Google Scholar
  8. 8.
    McLuckey, S. A.; Goeringer, D. E. Slow Heating Methods in Tandem Mass Spectrometry. J. Mass Spectrom. 1997, 32, 461–474.CrossRefGoogle Scholar
  9. 9.
    Paizs, B.; Suhai, S. Fragmentation Pathways of Protonated Peptides. Mass Spectrom. Rev. 2005, 24, 508–548.CrossRefGoogle Scholar
  10. 10.
    Armentrout, P. B. Mass Spectrometry—Not Just a Structural Tool: The Use of Guided Ion Beam Tandem Mass Spectrometry to Determine Thermochemistry. J. Am. Soc. Mass Spectrom. 2002, 13, 419–434.CrossRefGoogle Scholar
  11. 11.
    Armentrout, P. B. Statistical Modeling of Sequential Collision-Induced Dissociation Thresholds. J. Chem. Phys. 2007, 126, 234–302.CrossRefGoogle Scholar
  12. 12.
    Biemann, K. Contributions of Mass Spectrometry to Peptide and Protein Structure. Biomed. Environ. Mass Spectrom. 1984, 16, 99–111.CrossRefGoogle Scholar
  13. 13.
    Harrison, A. G.; Csizmadia, I. G.; Tang, T.-H.; Tu, Y.-P. Reaction Competition in the Fragmentation of Protonated Dipeptides. J. Mass Spectrom. 2000, 35, 683–688.CrossRefGoogle Scholar
  14. 14.
    Roepstorff, P.; Fohlman, J. Proposal for a Common Nomenclature for Sequence Ions in Mass-Spectra of Peptides. Biomed. Mass Spectrom. 1984, 11, 601–601.CrossRefGoogle Scholar
  15. 15.
    Tabb, D. L.; Smith, L. L.; Breci, L. A.; Wysocki, V. H.; Lin, D.; Yates, J. R. Statistical Characterization of Ion Trap Tandem Mass Spectra from Doubly Charged Tryptic Peptides. Anal. Chem. 2003, 75, 1155–1163.CrossRefGoogle Scholar
  16. 16.
    Wysocki, V. H.; Tsaprailis, G.; Smith, L. L.; Breci, L. A. Mobile and Localized Protons: A Framework for Understanding Peptide Dissociation. J. Mass Spectrom. 2000, 35, 1399–1406.CrossRefGoogle Scholar
  17. 17.
    Polce, M. J.; Ren, D.; Wesdemiotis, C. Dissociation of the Peptide Bond in Protonated Peptides. J. Mass Spectrom. 2000, 35, 1391–1398.CrossRefGoogle Scholar
  18. 18.
    Laskin, J.; Futrell, J. H. Collisional Activation of Peptide Ions in FT-ICR Mass Spectrometry. Mass Spectrom. Rev. 2003, 22, 158–181.CrossRefGoogle Scholar
  19. 19.
    Laskin, J.; Byrd, M.; Futrell, J. Internal Energy Distributions Resulting from Sustained Off-Resonance Excitation in FTMS. I. Fragmentation of the Bromobenzene Radical Cation. Int. J. Mass Spectrom. 2000, 195, 285–302.CrossRefGoogle Scholar
  20. 20.
    Muntean, F.; Armentrout, P. B. Guided Ion Beam Study of Collision-Induced Dissociation Dynamics: Integral and Differential Cross Sections. J. Chem. Phys. 2001, 115, 1213–1228.CrossRefGoogle Scholar
  21. 21.
    Meroueh, O.; Hase, W. L. Collisional Activation of Small Peptides. J. Phys. Chem. A 1999, 103, 3981–3990.CrossRefGoogle Scholar
  22. 22.
    Meroueh, O.; Hase, W. L. Energy Transfer Pathways in the Collisional Activation of Peptides. Int. J. Mass Spectrom. 2000, 201, 233–244.CrossRefGoogle Scholar
  23. 23.
    Marzluff, E. M.; Campbell, S.; Rodgers, M. T.; Beauchamp, J. L. Collisional Activation of Large Molecules is an Efficient Process. J. Am. Chem. Soc. 1994, 116, 6947–6948.CrossRefGoogle Scholar
  24. 24.
    Marzluff, E. M.; Campbell, S.; Rodgers, M. T.; Beauchamp, J. L. Low-Energy Dissociation Pathways of Small Deprotonated Peptides in the Gas Phase. J. Am. Chem. Soc. 1994, 116, 7787–7796.CrossRefGoogle Scholar
  25. 25.
    Alexander, A. J.; Boyd, R. K. Experimental Investigations of Factors Controlling the Collision-Induced Dissociation Spectra of Peptide Ions in a Tandem Hybrid Mass Spectrometer. 1: Leucine Enkephalin. Int. J. Mass Spectrom. Ion Processes 1989, 90, 211–240.CrossRefGoogle Scholar
  26. 26.
    Alexander, A. J.; Thibault, P.; Boyd, R. K. Target Gas Excitation in Collision-Induced Dissociation—a Reinvestigation of Energy Loss in Collisional Activation of Molecular Ions of Chlorophyll-α. J. Am. Chem. Soc. 1990, 112, 2484–2491.CrossRefGoogle Scholar
  27. 27.
    Thibault, P.; Alexander, A. J.; Boyd, R. K. High-Energy Collisional Activation Studied Via Angle-Resolved Translational Energy Spectra of Survivor Ions. J. Am. Soc. Mass Spectrom. 1993, 4, 835–844.CrossRefGoogle Scholar
  28. 28.
    Thibault, P.; Alexander, A. J.; Boyd, R. K.; Tomer,. K. B. Delayed Dissociation Spectra of Survivor Ions from High-Energy Collisional Activation. J. Am. Soc. Mass Spectrom. 1993, 4, 845–854.CrossRefGoogle Scholar
  29. 29.
    Chen, G.; Cooks, R. G.; Bunk, D. M.; Welch, M. J.; Christie, J. R. Partitioning of Kinetic Energy to Internal Energy in the Low Energy Collision-Induced Dissociation of Proton-Bound Dimers of Polypeptides. Int. J. Mass Spectrom. 1999, 185/186/187, 75–90.CrossRefGoogle Scholar
  30. 30.
    Heeren, R. M. A.; Vekey, K. A Novel Method to Determine Collisional Energy Transfer Efficiency by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. Rapid Commun. Mass Spectrom. 1998, 12, 1175–1181.CrossRefGoogle Scholar
  31. 31.
    Collette, C.; De Pauw, E. Calibration of the Internal Energy Distribution of Ions Produced by Electrospray. Rapid Commun. Mass Spectrom. 1998, 12, 165–170.CrossRefGoogle Scholar
  32. 32.
    Collette, C.; Drahos, L.; De Pauw, E.; Vekey, K. Comparison of the Internal Energy Distributions of Ions Produced by Different Electrospray Sources. Rapid Commun. Mass Spectrom. 1998, 12, 1673–1678.CrossRefGoogle Scholar
  33. 33.
    Drahos, L.; Heeren, R. M. A.; Collette, C.; De Pauw, E.; Vekey, K. Thermal Energy Distribution Observed in Electrospray Ionization. J. Mass Spectrom. 1999, 34, 1373–1379.CrossRefGoogle Scholar
  34. 34.
    Drahos, L.; Sztaray, J.; Vekey, K. Theoretical Calculation of Isotope Effects, Kinetic Energy Release, and Effective Temperatures for Slkylamines. Int. J. Mass Spectrom. 2003, 225, 233–248.CrossRefGoogle Scholar
  35. 35.
    Drahos, L.; Vekey, K. Mass Kinetics: A Theoretical Model of Mass Spectra Incorporating Physical Processes, Reaction Kinetics, and Mathematical dDescription. J. Mass Spectrom. 2001, 36, 237–263.CrossRefGoogle Scholar
  36. 36.
    Naban-Maillet, J.; Lesage, D.; Bossee, A.; Gimbert, Y.; Sztaray, J.; Vekey, K.; Tabet, J. C. Internal Energy Distribution in Electrospray Ionization. J. Mass Spectrom. 2005, 40, 1–8.CrossRefGoogle Scholar
  37. 37.
    Pak, A.; Lesage, D.; Gimbert, Y.; Vekey, K.; Tabet, J. C. Internal Energy Distribution of Peptides in Electrospray Ionization: ESI and Collision-Induced Dissociation Spectra Calculation. J. Mass Spectrom. 2008, 43, 447–455.CrossRefGoogle Scholar
  38. 38.
    Laskin, J.; Denisov, E.; Futrell, J. H. A Comparative Study of Collision-Induced and Surface-Induced Dissociation. 1: Fragmentation of Protonated Dialanine. J. Am. Chem. Soc. 2000, 122, 9703–9714.CrossRefGoogle Scholar
  39. 39.
    Laskin, J.; Denisov, E.; Futrell, J. H. Comparative Study of Collision-Induced and Surface-Induced Dissociation. 2: Fragmentation of Small Alanine-Containing Peptides in FT-ICR MS. J. Phys. Chem. B 2001, 105, 1895–1900.CrossRefGoogle Scholar
  40. 40.
    Laskin, J.; Denisov, E.; Futrell, J. H. Fragmentation Energetics of Small Peptides from Multiple-Collision Activation and Surface-Induced Dissociation in FT-ICR MS. Int. J. Mass Spectrom. 2002, 219, 189–201.CrossRefGoogle Scholar
  41. 41.
    Laskin, J.; Futrell, J. H. Internal Energy Distributions Resulting from Sustained Off-Resonance Excitation in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: II. Fragmentation of the 1-Bromonaphthalene Radical Cation. J. Phys. Chem. A 2000, 104, 5484–5494.CrossRefGoogle Scholar
  42. 42.
    Laskin, J.; Futrell, J. H. On the Efficiency of Energy Transfer in Collisional Activation of Small Peptides. J. Chem. Phys. 2002, 116, 4302–4310.CrossRefGoogle Scholar
  43. 43.
    Muntean, F.; Armentrout, P. B. Modeling Kinetic Shifts and Competition in Threshold Collision-Induced Dissociation: Case study: n-Butylbenzene Cation Dissociation. J. Phys. Chem. A 2003, 107, 7413–7422.CrossRefGoogle Scholar
  44. 44.
    Armentrout, P. B. Threshold Collision-Induced Dissociations for the Determination of Accurate Gas-Phase Binding Energies and Reaction Barriers. Modern Mass Spectrom. 2003, 225, 233–262.CrossRefGoogle Scholar
  45. 45.
    Khan, F. A. C. D. E.; Schultz, R. H.; Armentrout, P. B. Sequential Bond-Energies of Cr(CO)x+, x = 1–6. J. Phys. Chem. 1993, 97, 7978–7987.CrossRefGoogle Scholar
  46. 46.
    Rodgers, M. T.; Ervin, K. M.; Armentrout, P. B. Statistical Modeling of Collision-Induced Dissociation Thresholds. J. Chem. Phys. 1997, 106, 4499–4508.CrossRefGoogle Scholar
  47. 47.
    Martinez-Nunez, E.; Fernandez-Ramos, A.; Vasquez, S. A.; Marques, J.; Xue, M.; Hase, W. L. Quasiclassical Dynamics Simulation of the Collision-Induced dissociation Cr(CO)6+ with Xe. J. Chem. Phys. 2006, 123, 154311.CrossRefGoogle Scholar
  48. 48.
    Certain commercial instruments and materials are identified in this article to adequately specify the procedures. In no case does such identification imply recommendation or endorsement by NIST, nor does it imply that the instruments or materials are necessarily the best available for this purpose.Google Scholar
  49. 49.
    Becke, A. D. A New Mixing of Hartree-Fock and Local Density-Functional Theories. J. Chem. Phys. 1993, 98, 1372–1377.CrossRefGoogle Scholar
  50. 50.
    Lee, C. T.; Yang, W. T.; Parr, R. G. Development of the Colle-Salvetti Correlation-Energy Formula into a Functional of the Electron Density. Phys. Rev. B 1988, 37, 785–789.CrossRefGoogle Scholar
  51. 51.
    Cizek, J. Use of the Cluster Expansion and the Technique of Diagrams in Calculations of Correlation Effects in Atoms and Molecules. Adv. Chem. Phys. 1969, 14, 35–89.Google Scholar
  52. 52.
    Bartlett, R. J.; Purvis, G. D. Many-Body Perturbation-Theory, Coupled-Pair Many-Electron Theory, and Importance of Quadruple Excitations for Correlation Problem. Int. J. Quant. Chem. 1978, 14, 516–581.CrossRefGoogle Scholar
  53. 53.
    Purvis, G. D. I.; Bartlett, R. J. A Full Coupled-Cluster Singles and Doubles Model: The Inclusion of Disconnected Triples. J. Chem. Phys. 1982, 76, 1910–1918.CrossRefGoogle Scholar
  54. 54.
    Kendall, R. A.; Dunning, T. H., Jr.; Harrison, R. J. Electron Affinities of the First-Row Atoms Revisited: Systematic Basis Sets and Wave Functions. J. Chem. Phys. 1992, 96, 6796–6806.CrossRefGoogle Scholar
  55. 55.
    Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery, J. A. Jr.; Vreven, T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian 03Revision C 02; Gaussian, Inc.: Wallingford, CT, 2004.Google Scholar
  56. 56.
    Durant, J. L. Evaluation of Transition State Properties by Density Functional Theory. Chem. Phys. Lett 1996, 256, 595–602.CrossRefGoogle Scholar
  57. 57.
    Duncan, W. T.; Truong, T. N. Thermal and Vibrational-State Selected Rates of the CH4+Cl→HCl + CH3 Reaction. J. Chem. Phys. 1995, 103, 9642–9652.CrossRefGoogle Scholar
  58. 58.
    Maity, D. K.; Duncan, W. T.; Truong, T. N. Direct Ab Initio Dynamics Studies of the Hydrogen Abstraction Reactions of Hydrogen Atom with Fluoromethanes. J. Phys. Chem. A 1999, 103, 2152–2159.CrossRefGoogle Scholar
  59. 59.
    Truong, T. N. A Direct Ab-Initio Dynamics Approach for Calculating Thermal Rate Constants Using Variational Transition-State Theory and Multidimensional Semiclassical Tunneling Methods—an Application to the CH4 + H→CH3+H2 Reaction. J. Chem. Phys. 1994, 100, 8014–8025.CrossRefGoogle Scholar
  60. 60.
    Truong, T. N.; Duncan, W. T.; Bell, R. L. Direct Ab Initio Dynamics Methods for Calculating Thermal Rates of Polyatomic Reactions In Chemical Applications of Density Functional Theory; Laird, B. B.; Ross, R. B.; Ziegler, T., Eds.; American Chemical Society: Washington, DC, 1996; pp 85–104.CrossRefGoogle Scholar
  61. 61.
    Mora-Diez, N.; Boyd, R. J. A Computational Study of the Kinetics of the NO3 Hydrogen-Abstraction Reaction from a Series of Aldehydes (XCHO: X = F, Cl, H, CH3). J. Phys. Chem. A 2002, 106, 384–394.CrossRefGoogle Scholar
  62. 62.
    Knyazev, V. D. Reactivity Extrapolation from Small to Large Molecular Systems Via Isodesmic Reactions for Transition States (RESLIR). J. Phys. Chem. 2004, 108, 10714–10722.CrossRefGoogle Scholar
  63. 63.
    Benson, S. W. Thermochemical Kinetics; 2nd Ed.; John Wiley and Sons: New York, 1976.Google Scholar
  64. 64.
    Robinson, P. J.; Holbrook, K. A. Unimolecular Reactions; Wiley-InterScience: New York, 1972.Google Scholar
  65. 65.
    Gilbert, R. G.; Smith, S. C. Theory of Unimolecular and Recombination Reactions; Blackwell: Oxford, 1990.Google Scholar
  66. 66.
    Holbrook, K. A.; Pilling, M. J.; Robertson, S. H. Unimolecular Reactions; 2nd ed. Wiley: New York, 1996.Google Scholar
  67. 67.
    Chase, M. W., Jr. NIST-JANAF Thermochemical Tables, 4th Edition. Monograph. J. Phys. Chem. Ref. Data 1998, 9, 1–1951.Google Scholar
  68. 68.
    Carson, A. S.; Laye, P. G.; Yrekli, M. The Enthalpy of Formation of Benzylamine. J. Chem. Thermodyn 1977, 9, 827–829.CrossRefGoogle Scholar
  69. 69.
    Tsang, W. Heats of Formation of Organic Free Radicals by Kinetic Methods In Energetics of Organic Free Radicals; Martinho Simoes, J. A.; Greenberg, A.; Liebman, J. F., Eds.; Blackie Academic and Professional: London, 1996; pp 22–58.CrossRefGoogle Scholar
  70. 70.
    Lias, S. G. Ionization Energy Evaluation for Benzyl Radical. Web Page,, accessed Sept. 2, 2008.Google Scholar
  71. 71.
    Hunter, E. P.; Lias, S. G. Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update. J. Phys. Chem. Ref. Data 1998, 27, 413–656.CrossRefGoogle Scholar
  72. 72.
    Colclough, A. R. Two Theories of Experimental Error. J. Res. Nat. Bur. Stand 1987, 92, 167–185.CrossRefGoogle Scholar
  73. 73.
    Baer, T.; Hase, W. L. Unimolecular Reaction Dynamics; Oxford University Press: New York, 1996; 324–368.Google Scholar
  74. 74.
    Lim, K. F.; Hase, W. L. MARINER: A General Monte Carlo Classical Trajectory Program., 1990.Google Scholar
  75. 75.
    Hase, W. L.; Duchovic, R. J.; Hu, X.; Komornicki, A.; Lim, K. F.; Lu, D.-H.; Peslherbe, G. H.; Swamy, K. N.; Vande Linde, S. R.; Varandas, A.; Wang, H.; Wolf, R. J. VENUS96: A General Chemical Dynamics Computer Program. Quantum Chem. Program Exchange Bull. 1996, 16, 43.Google Scholar
  76. 76.
    Cornell, W. D.; Cieplak, P.; Bayly, C. I.; Gould, I. R.; Merz, K. M.; Ferguson, D. M.; Spellmeyer, D. C.; Fox, T.; Caldwell, J. W.; Kollman, P. A. A Second Generation Force-Field for the Simulation of Proteins, Nucleic-Acids, and Organic Molecules. J. Am. Chem. Soc. 1995, 117, 5179–5197.CrossRefGoogle Scholar
  77. 77.
    Jorgensen, W. L.; Maxwell, D. S.; Tirado-Rives, J. Development and Testing of the OPLS All-Atom Force Field on Conformational Energetics and Properties of Organic Liquids. J. Am. Chem. Soc. 1996, 118, 11225–11236.CrossRefGoogle Scholar
  78. 78.
    Price, M. L. P.; Ostrovsky, D.; Jorgensen, W. L. Gas-Phase and Liquid-State Properties of Esters, Nitriles, and Nitro Compounds with the OPLS-AA Force Field. J. Comput. Chem. 2001, 22, 1340–1352.CrossRefGoogle Scholar
  79. 79.
    Pople, J. A.; Head-Gordon, M.; Raghavachari, K. Quadratic Configuration Interaction: A General Technique for Determining Electron Correlation Energies. J. Chem. Phys. 1987, 87, 5968–5975.CrossRefGoogle Scholar
  80. 80.
    Friedman, M. H.; Yergey, A. L.; Campana, J. E. Fundamentals of Ion Motion in Electric Radio-Frequency Multipole Fields. J. Phys. E: Sci. Instrum 1982, 15, 53–61.CrossRefGoogle Scholar
  81. 81.
    Scientific Instrument Services, I. SIMION, Simulation Software for Modeling of Electron and Ion Optics; Ringoes, NJ, 2004.Google Scholar
  82. 82.
    Fenn, P. T.; Chen, Y. J.; Stimson, S.; Ng, C. Y. Dissociation of CH3SH+ by Collisional Activation: Evidence of Nonstatistical Behavior. J. Phys. Chem. A 1997, 101, 6513–6522.CrossRefGoogle Scholar
  83. 83.
    Chen, Y. J.; Fenn, P. T.; Lau, K. C.; Ng, C. Y.; Law, C. K.; Li, W. K. Study of the dissociation of CH3SCH3+ by Collisional Activation: Evidence of Nonstatistical Behavior. J. Phys. Chem. A 202, 106, 9729–9736.Google Scholar
  84. 84.
    Martinez-Nunez, E.; Vazquez, S. A. Dynamics of Unimolecular Reactions in Gas Phase Deviations from Statistical Behavior. Quimica Nova 2002, 25, 579–588.CrossRefGoogle Scholar
  85. 85.
    Martínez-Núñez, E.; Vázquez, S. A.; Aoiz, F. J.; Castillo, J. F. Quasiclassical Trajectory Study of the Collision-Induced Dissociation Dynamics of Ar + CH3SH+ Using an Ab Initio Interpolated Potential Energy Surface. J. Phys. Chem. A 2006, 110, 1225–1231.CrossRefGoogle Scholar

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© American Society for Mass Spectrometry 2010

Authors and Affiliations

  1. 1.National Institute of Standards and TechnologyPhysical and Chemical Properties DivisionGaithersburgUSA
  2. 2.Research Center for Chemical Kinetics, Department of ChemistryThe Catholic University of AmericaWashingtonUSA

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