Dissociation rates of energy-selected benzene cations: comparison of experimental results from ion cyclotron resonance and cylindrical ion trap time-of-flight mass spectrometry

Grebner, Th.L.; Neusser, H. J.

doi:10.1016/s1387-3806(98)14157-x

Cited by 15 publications

(16 citation statements)

References 28 publications

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“…In this study, we investigated the energy deposition process observed in fluorinated SAM-SID of the benzene molecular cation. The fragmentation of benzene radical cation has been extensively studied using different experimental and theoretical approaches, − and the energetics and dynamics of its major fragmentation pathways are well-established. Although a relatively small molecular ion, the benzene molecular ion, C 6 H 6 +• possesses several features of a “medium-to-large” ionic system.…”

Section: Introductionmentioning

confidence: 99%

Surface-Induced Dissociation of the Benzene Molecular Cation in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

2002

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Energy transfer in collisions of benzene molecular ions with a fluorinated self-assembled monolayer surface at normal incidence was studied over the range of collision energies from 0 to 75 eV in a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). Rice-Ramsperger-Kassel-Marcus (RRKM) theory was used to calculate breakdown graphs for a simplified decomposition scheme of benzene on the time scale of ICR MS detection. Statistical partitioning of excess internal energy between the neutral and the ionic products was included in the theoretical model. Internal energy distributions of the predissociating parent ions were iteratively calculated using the recursive internal energy distribution search (RIEDS) method for each collision energy. On the basis of the above measurements, the collision-energy-dependent E SID f E int energy conversion efficiency was found to maximize at about 19.5% under the conditions of 31 eV SID collision energy.

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Section: Introductionmentioning

confidence: 99%

Surface-Induced Dissociation of the Benzene Molecular Cation in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

2002

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“…The benzene molecular ion has been used as a model system for internal energy deposition since its breakdown behavior is well known. 26,27 Using a deconvolution method this ion was found to give similar data to the thermometer method and somewhat higher T→V conversion efficiencies were found with this method in the case of SID in a Fourier transform ion cyclotron resonance (FT-ICR) instrument: 17% in the case of the H-SAM surface and 28% for the F-SAM. 28 Both methods just discussed give P(ε) curves with discrete points limited by the number of useable peaks in the mass spectrum.…”

mentioning

confidence: 76%

Translational to Vibrational Energy Conversion during Surface-Induced Dissociation of N-Butylbenzene Molecular Ions Colliding at Self-Assembled Monolayer Surfaces

Cooks

2003

Eur J Mass Spectrom (Chichester)

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Translational to vibrational (T-->V) energy conversion in the course of inelastic collisions of n-butylbenzene molecular ions with thiolate self-assembled monolayer (SAM) gold surfaces is studied to better understand internal energy uptake by the hyperthermal projectile ions. The projectile ion is selected by a mass spectrometer of BE configuration and product ions are analyzed using a quadrupole mass analyzer after kinetic energy selection with an electric sector. The branching ratio for formation of the fragment ions m/z 91 and m/z 92, measured over a range of collision energies, is used to estimate the average internal energy with the aid of calculations based on unimolecular dissociation kinetics [Rice-Ramsperger-Kassel-Marcus (RRKM) theory]. The measured T-->V conversion efficiencies (the fraction of the laboratory kinetic energy converted into internal energy) are 11 approximately 12% for dodecanethiolate SAM (H-SAM) and 19 approximately 20% for 2-perfluorooctylethanethiolate SAM (F-SAM), respectively, over ranges of a few 10s of eV. The values are similar to those reported earlier for other thermometer molecules undergoing surface collisions. Chemical sputtering leading to ionization of the surface is a prominent feature of the surface-induced dissociation (SID) spectra of n-butylbenzene acquired using the H-SAM surface but not the F-SAM surface because of the lower ionization energy of the former.

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“…where N is a normalization factor, k(E) is the dissociation rate constant, whose variation with internal energy is available for C 6 H 6 +3,4,7,9,11,12,14-17 and C 6 D 6 + . 12,14,15 R(E) is the branching ratio for the hydrogen loss channel. 11 To sample different internal energy ranges, three translational energies of the ionic fragment (2, 5, and 8 keV in the laboratory frame) were selected.…”

Section: Methodsmentioning

confidence: 99%

Hydrogen Atom Loss from the Benzene Cation. Why Is the Kinetic Energy Release so Large?

et al. 2006

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The kinetic energy release distributions (KERDs) associated with the hydrogen loss from the benzene cation and the deuterium loss from the perdeuteriobenzene cation have been remeasured on the metastable time scale and analyzed by the maximum entropy method. The experimental kinetic energy releases are larger than expected statistically, in contradistinction to what has been observed for the C-X fragmentations of the halogenobenzene cations. H(D) loss from C(6)H(6)(+) (C(6)D(6)(+)) occurs via a conical intersection connecting the (2)A(2) and (2)A(1) electronic states. Two models are proposed to account for the experimental data: (i) a modified orbiting transition state theory (OTST) approach incorporating electronic nonadiabaticity; (ii) an electronically nonadiabatic version of the statistical adiabatic channel model (SACM) of Quack and Troe. The latter approach is found to be preferable. It leads to the conclusion that the larger the energy stored in the transitional modes, which partly convert to the relative interfragment motion, the shorter the value of the reaction coordinate at which the adiabatic channels cross, and the larger the probability of undergoing the (2)A(2) --> (2)A(1) transition required for hydrogen loss.

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Dissociation rates of energy-selected benzene cations: comparison of experimental results from ion cyclotron resonance and cylindrical ion trap time-of-flight mass spectrometry

Cited by 15 publications

References 28 publications

Surface-Induced Dissociation of the Benzene Molecular Cation in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Surface-Induced Dissociation of the Benzene Molecular Cation in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Translational to Vibrational Energy Conversion during Surface-Induced Dissociation of N-Butylbenzene Molecular Ions Colliding at Self-Assembled Monolayer Surfaces

Hydrogen Atom Loss from the Benzene Cation. Why Is the Kinetic Energy Release so Large?

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